LVDS panel compatible strings

Hi everyone,

I've been working on converting all Tegra-related device tree bindings to json-schema so that eventually we can fully validate device tree files. Getting all the bindings reviewed and merged has been slow, but I have a local tree where pretty much all validation errors and warnings have been fixed. The remaining warnings that I'm not sure how to resolve are these:

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

The reason for these is that the device tree files use:

        compatible = "panel-lvds";

but that's not valid as per the bindings. So what we really want is a specific compatible string that specifies the exact panel that each of these devices uses in addition to the "panel-lvds" fallback. Do you guys have information about these that could help fix up the DT files?

Thanks,
Thierry

пт, 14 лип. 2023 р. о 17:38 Thierry Reding <[email protected]> пише:

Quoted 26 lines

Hi everyone,

I've been working on converting all Tegra-related device tree bindings to json-schema so that eventually we can fully validate device tree files. Getting all the bindings reviewed and merged has been slow, but I have a local tree where pretty much all validation errors and warnings have been fixed. The remaining warnings that I'm not sure how to resolve are these:

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Quoted 8 lines

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Hello Thierry! Pegatron Chagall uses a Hannstar similar to one used in ASUS TF201 but unfortunately it is not compatible with existing simple panel setup (blurry image if used). My assumption is that chagall as different revision of this panel like HSD101PWW3-B00 or HSD101PWW1-A00 which is more likely or panel is highly modified which is unlikely. I propose to use "hannstar,hsd101pww1" which is more wide spread.

Quoted 36 lines

пт, 14 лип. 2023 р. о 17:38 Thierry Reding <[email protected]> пише:

Quoted 26 lines

Hi everyone,

I've been working on converting all Tegra-related device tree bindings to json-schema so that eventually we can fully validate device tree files. Getting all the bindings reviewed and merged has been slow, but I have a local tree where pretty much all validation errors and warnings have been fixed. The remaining warnings that I'm not sure how to resolve are these:

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Quoted 8 lines

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Quoted 7 lines

Hello Thierry! Pegatron Chagall uses a Hannstar similar to one used in ASUS TF201 but unfortunately it is not compatible with existing simple panel setup (blurry image if used). My assumption is that chagall as different revision of this panel like HSD101PWW3-B00 or HSD101PWW1-A00 which is more likely or panel is highly modified which is unlikely. I propose to use "hannstar,hsd101pww1" which is more wide spread.

Interesting. So is the problem the HSD101PWW2 timings that are off, or is it because the panel-lvds code does something special to make this blurry image go away?

Thierry

пт, 14 лип. 2023 р. о 18:16 Thierry Reding <[email protected]> пише:

Quoted 46 lines · Svyatoslav Ryhel

Quoted 43 lines

пт, 14 лип. 2023 р. о 17:38 Thierry Reding <[email protected]> пише:

Quoted 26 lines

Hi everyone,

I've been working on converting all Tegra-related device tree bindings to json-schema so that eventually we can fully validate device tree files. Getting all the bindings reviewed and merged has been slow, but I have a local tree where pretty much all validation errors and warnings have been fixed. The remaining warnings that I'm not sure how to resolve are these:

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Quoted 8 lines

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Hello Thierry! Pegatron Chagall uses a Hannstar similar to one used in ASUS TF201 but unfortunately it is not compatible with existing simple panel setup (blurry image if used). My assumption is that chagall as different revision of this panel like HSD101PWW3-B00 or HSD101PWW1-A00 which is more likely or panel is highly modified which is unlikely. I propose to use "hannstar,hsd101pww1" which is more wide spread.

Quoted 4 lines

Interesting. So is the problem the HSD101PWW2 timings that are off, or is it because the panel-lvds code does something special to make this blurry image go away?

timings are different

Quoted 47 lines

пт, 14 лип. 2023 р. о 18:16 Thierry Reding <[email protected]> пише:

Quoted 46 lines · Svyatoslav Ryhel

Quoted 43 lines

пт, 14 лип. 2023 р. о 17:38 Thierry Reding <[email protected]> пише:

Quoted 26 lines

Hi everyone,

I've been working on converting all Tegra-related device tree bindings to json-schema so that eventually we can fully validate device tree files. Getting all the bindings reviewed and merged has been slow, but I have a local tree where pretty much all validation errors and warnings have been fixed. The remaining warnings that I'm not sure how to resolve are these:

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Quoted 8 lines

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Hello Thierry! Pegatron Chagall uses a Hannstar similar to one used in ASUS TF201 but unfortunately it is not compatible with existing simple panel setup (blurry image if used). My assumption is that chagall as different revision of this panel like HSD101PWW3-B00 or HSD101PWW1-A00 which is more likely or panel is highly modified which is unlikely. I propose to use "hannstar,hsd101pww1" which is more wide spread.

Quoted 5 lines

Quoted 4 lines

Interesting. So is the problem the HSD101PWW2 timings that are off, or is it because the panel-lvds code does something special to make this blurry image go away?

timings are different

For cases where the timings are the only things that differ, the DT bindings allow overriding the timings specifically. So you might get away with using one of the existing panels if it is close enough and patch up the timings in DT.

Comparing what you've got for Chagall, the porches exceed what the HSD101PWW2 allows, but the timing values in the simple-panel driver look a little arbitrary, to be honest, so I think those could be extended. Looking at a datasheet that I found online, it's very unspecific about the porch lengths since it only mentions minimum, typical and maximum values for the total frame blanking times:

	vertical: 3, 23, 223
	horizontal: 54, 160, 681

So I think we can be more generous in how these are split up. So we could for example do this:

--- >8 ---

drivers/gpu/drm/panel/panel-simple.c +6 -7

index 18dc251749fb..b2fb7943f2ed 100644
@@ -2108,13 +2108,13 @@ static const struct panel_desc hannstar_hsd100pxn1 = {
 static const struct display_timing hannstar_hsd101pww2_timing = {
 	.pixelclock = { 64300000, 71100000, 82000000 },
 	.hactive = { 1280, 1280, 1280 },
-	.hfront_porch = { 1, 1, 10 },
-	.hback_porch = { 1, 1, 10 },
-	.hsync_len = { 58, 158, 661 },
+	.hfront_porch = { 1, 1, 64 },
+	.hback_porch = { 1, 1, 64 },
+	.hsync_len = { 58, 158, 553 },
 	.vactive = { 800, 800, 800 },
-	.vfront_porch = { 1, 1, 10 },
-	.vback_porch = { 1, 1, 10 },
-	.vsync_len = { 1, 21, 203 },
+	.vfront_porch = { 1, 1, 32 },
+	.vback_porch = { 1, 1, 32 },
+	.vsync_len = { 1, 21, 159 },
 	.flags = DISPLAY_FLAGS_DE_HIGH,
 };
 
--- >8 ---

And then we could move the compatible string from simple to LVDS:

--- >8 ---

Documentation/devicetree/bindings/display/panel/panel-lvds.yaml +2 -0

index 929fe046d1e7..344e5df40c2f 100644
@@ -40,6 +40,8 @@ properties:
    items:
      - enum:
          - auo,b101ew05
+          # HannStar Display Corp. HSD101PWW2 10.1" WXGA (1280x800) LVDS panel
+          - hannstar,hsd101pww2
          - tbs,a711-panel
 
      - const: panel-lvds

Documentation/devicetree/bindings/display/panel/panel-simple.yaml +0 -2

index df1cec8fd21b..f4d9da4afefd 100644
@@ -168,8 +168,6 @@ properties:
      - hannstar,hsd070pww1
        # HannStar Display Corp. HSD100PXN1 10.1" XGA LVDS panel
      - hannstar,hsd100pxn1
-        # HannStar Display Corp. HSD101PWW2 10.1" WXGA (1280x800) LVDS panel
-      - hannstar,hsd101pww2
        # Hitachi Ltd. Corporation 9" WVGA (800x480) TFT LCD panel
      - hit,tx23d38vm0caa
        # InfoVision Optoelectronics M133NWF4 R0 13.3" FHD (1920x1080) TFT LCD panel

arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dts +1 -2

index c81d5875c31c..4012f9c799a8 100644
@@ -2628,7 +2628,7 @@ cpu3: cpu@3 {
 	};
 
 	display-panel {
-		compatible = "panel-lvds";
+		compatible = "hannstar,hsd101pww2", "panel-lvds";
 
 		width-mm = <217>;
 		height-mm = <136>;
--- >8 ---

That gets rid of the DT validation warning for me. Would you be able to test this on actual hardware? I think the compatible matching would result in this matching the simple-panel driver and that does have some support for LVDS, but I'm not sure if it's exactly equal to what you get with only the panel-lvds matching, which makes this get handled by the panel-lvds driver.

I'm attaching the full patch to make it a bit easier to apply this.

Thierry

Quoted 47 lines

пт, 14 лип. 2023 р. о 18:16 Thierry Reding <[email protected]> пише:

Quoted 46 lines · Svyatoslav Ryhel

Quoted 43 lines

пт, 14 лип. 2023 р. о 17:38 Thierry Reding <[email protected]> пише:

Quoted 26 lines

Hi everyone,

I've been working on converting all Tegra-related device tree bindings to json-schema so that eventually we can fully validate device tree files. Getting all the bindings reviewed and merged has been slow, but I have a local tree where pretty much all validation errors and warnings have been fixed. The remaining warnings that I'm not sure how to resolve are these:

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Quoted 8 lines

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Hello Thierry! Pegatron Chagall uses a Hannstar similar to one used in ASUS TF201 but unfortunately it is not compatible with existing simple panel setup (blurry image if used). My assumption is that chagall as different revision of this panel like HSD101PWW3-B00 or HSD101PWW1-A00 which is more likely or panel is highly modified which is unlikely. I propose to use "hannstar,hsd101pww1" which is more wide spread.

Quoted 5 lines

Quoted 4 lines

Interesting. So is the problem the HSD101PWW2 timings that are off, or is it because the panel-lvds code does something special to make this blurry image go away?

timings are different

For cases where the timings are the only things that differ, the DT bindings allow overriding the timings specifically. So you might get away with using one of the existing panels if it is close enough and patch up the timings in DT.

Comparing what you've got for Chagall, the porches exceed what the HSD101PWW2 allows, but the timing values in the simple-panel driver look a little arbitrary, to be honest, so I think those could be extended. Looking at a datasheet that I found online, it's very unspecific about the porch lengths since it only mentions minimum, typical and maximum values for the total frame blanking times:

        vertical: 3, 23, 223
        horizontal: 54, 160, 681

So I think we can be more generous in how these are split up. So we could for example do this:

--- >8 ---

drivers/gpu/drm/panel/panel-simple.c +6 -7

index 18dc251749fb..b2fb7943f2ed 100644
@@ -2108,13 +2108,13 @@ static const struct panel_desc hannstar_hsd100pxn1 = {
 static const struct display_timing hannstar_hsd101pww2_timing = {
        .pixelclock = { 64300000, 71100000, 82000000 },
        .hactive = { 1280, 1280, 1280 },
-       .hfront_porch = { 1, 1, 10 },
-       .hback_porch = { 1, 1, 10 },
-       .hsync_len = { 58, 158, 661 },
+       .hfront_porch = { 1, 1, 64 },
+       .hback_porch = { 1, 1, 64 },
+       .hsync_len = { 58, 158, 553 },
        .vactive = { 800, 800, 800 },
-       .vfront_porch = { 1, 1, 10 },
-       .vback_porch = { 1, 1, 10 },
-       .vsync_len = { 1, 21, 203 },
+       .vfront_porch = { 1, 1, 32 },
+       .vback_porch = { 1, 1, 32 },
+       .vsync_len = { 1, 21, 159 },
        .flags = DISPLAY_FLAGS_DE_HIGH,
 };
 
--- >8 ---

And then we could move the compatible string from simple to LVDS:

--- >8 ---

Documentation/devicetree/bindings/display/panel/panel-lvds.yaml +2 -0

index 929fe046d1e7..344e5df40c2f 100644
@@ -40,6 +40,8 @@ properties:
     items:
       - enum:
           - auo,b101ew05
+          # HannStar Display Corp. HSD101PWW2 10.1" WXGA (1280x800) LVDS panel
+          - hannstar,hsd101pww2
           - tbs,a711-panel
 
       - const: panel-lvds

Documentation/devicetree/bindings/display/panel/panel-simple.yaml +0 -2

index df1cec8fd21b..f4d9da4afefd 100644
@@ -168,8 +168,6 @@ properties:
       - hannstar,hsd070pww1
         # HannStar Display Corp. HSD100PXN1 10.1" XGA LVDS panel
       - hannstar,hsd100pxn1
-        # HannStar Display Corp. HSD101PWW2 10.1" WXGA (1280x800) LVDS panel
-      - hannstar,hsd101pww2
         # Hitachi Ltd. Corporation 9" WVGA (800x480) TFT LCD panel
       - hit,tx23d38vm0caa
         # InfoVision Optoelectronics M133NWF4 R0 13.3" FHD (1920x1080) TFT LCD panel

arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dts +1 -2

index c81d5875c31c..4012f9c799a8 100644
@@ -2628,7 +2628,7 @@ cpu3: cpu@3 {
        };
 
        display-panel {
-               compatible = "panel-lvds";
+               compatible = "hannstar,hsd101pww2", "panel-lvds";
 
                width-mm = <217>;
                height-mm = <136>;
--- >8 ---

That gets rid of the DT validation warning for me. Would you be able to test this on actual hardware? I think the compatible matching would result in this matching the simple-panel driver and that does have some support for LVDS, but I'm not sure if it's exactly equal to what you get with only the panel-lvds matching, which makes this get handled by the panel-lvds driver.

I'm attaching the full patch to make it a bit easier to apply this.

Thierry

For cases where the timings are the only things that differ, the DT bindings allow overriding the timings specifically. So you might get away with using one of the existing panels if it is close enough and patch up the timings in DT.

17.07.2023 10:16, Thierry Reding пишет:

Quoted 4 lines

For cases where the timings are the only things that differ, the DT bindings allow overriding the timings specifically. So you might get away with using one of the existing panels if it is close enough and patch up the timings in DT.

If panel-simple supported timings override from DT, then panel-lvds indeed could be removed. But panel-simple doesn't support it:

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a21f18a993c56566db94ba836684bc32c070a82c

Quoted 10 lines

17.07.2023 10:16, Thierry Reding пишет:

Quoted 4 lines

For cases where the timings are the only things that differ, the DT bindings allow overriding the timings specifically. So you might get away with using one of the existing panels if it is close enough and patch up the timings in DT.

If panel-simple supported timings override from DT, then panel-lvds indeed could be removed. But panel-simple doesn't support it:

https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=a21f18a993c56566db94ba836684bc32c070a82c

I clearly didn't look at that patch closely enough. panel-simple has supported override modes since:

commit b8a2948fa2b3a5a6da67fd57aa01c7318d795125

Author: Sean Paul <[email protected]>
Date:   Thu Jul 11 13:34:53 2019 -0700

drm/panel: simple: Add ability to override typical timing

This patch adds the ability to override the typical display timing for a given panel. This is useful for devices which have timing constraints that do not apply across the entire display driver (eg: to avoid crosstalk between panel and digitizer on certain laptops). The rules are as follows:

- panel must not specify fixed mode (since the override mode will either be the same as the fixed mode, or we'll be unable to check the bounds of the overried)
- panel must specify at least one display_timing range which will be used to ensure the override mode fits within its bounds

Changes in v2:
- Parse the full display-timings node (using the native-mode) (Rob)
Changes in v3:
- No longer parse display-timings subnode, use panel-timing (Rob)
Changes in v4:
- Don't add mode from timing if override was specified (Thierry)
- Add warning if timing and fixed mode was specified (Thierry)
- Don't add fixed mode if timing was specified (Thierry)
- Refactor/rename a bit to avoid extra indentation from "if" tests
- i should be unsigned (Thierry)
- Add annoying WARN_ONs for some cases (Thierry)
- Simplify 'No display_timing found' handling (Thierry)
- Rename to panel_simple_parse_override_mode() (Thierry)
Changes in v5:
- Added Heiko's Tested-by
Changes in v6:
- Rebased to drm-misc next
- Added tags

Cc Doug Anderson <[email protected]>

Cc Eric Anholt <[email protected]>

Cc Heiko Stuebner <[email protected]>

Cc Jeffy Chen <[email protected]>

Cc Rob Herring <[email protected]>

Cc Stéphane Marchesin <[email protected]>

Cc Thierry Reding <[email protected]>

Cc [email protected]

Cc [email protected]

Signed-off-by Sean Paul <[email protected]>

Tested-by Enric Balletbo i Serra <[email protected]>

Signed-off-by Douglas Anderson <[email protected]>

Tested-by Heiko Stuebner <[email protected]>

Reviewed-by Boris Brezillon <[email protected]>

Acked-by Thierry Reding <[email protected]>

Signed-off-by Sam Ravnborg <[email protected]>

Link https://patchwork.freedesktop.org/patch/msgid/[email protected]

Looking at the error message cited in the linked commit, the problem is that the Chunghwa panel has a fixed mode listed in the driver. However I don't see a reason why we can't get rid of that. The only place where I can find the compatible string for that used is for the Nexus 7, so we should be able to replace the fixed mode with the timings for that panel and remove the fixed mode.

The initial Chunghwa panel driver support doesn't seem to have been based on the Nexus 7, so I suppose if we make the above change we could technically be breaking some setup out there, but since we have no way of knowing which device this was on, or if anybody still has access, the best we can do is hope that nothing breaks and fix things up if somebody complains.

пт, 14 лип. 2023 р. о 17:38 Thierry Reding <[email protected]> пише:

Quoted 26 lines

Hi everyone,

I've been working on converting all Tegra-related device tree bindings to json-schema so that eventually we can fully validate device tree files. Getting all the bindings reviewed and merged has been slow, but I have a local tree where pretty much all validation errors and warnings have been fixed. The remaining warnings that I'm not sure how to resolve are these:

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-tilapia-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-E1565.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Quoted 8 lines

arch/arm/boot/dts/nvidia/tegra30-asus-nexus7-grouper-PM269.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible:0: 'panel-lvds' is not one of ['auo,b101ew05', 'tbs,a711-panel']
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: compatible: ['panel-lvds'] is too short
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#
arch/arm/boot/dts/nvidia/tegra30-pegatron-chagall.dtb: display-panel: Unevaluated properties are not allowed ('compatible' was unexpected)
from schema $id: http://devicetree.org/schemas/display/panel/panel-lvds.yaml#

Hello Thierry! Pegatron Chagall uses a Hannstar similar to one used in ASUS TF201 but unfortunately it is not compatible with existing simple panel setup (blurry image if used). My assumption is that chagall as different revision of this panel like HSD101PWW3-B00 or HSD101PWW1-A00 which is more likely or panel is highly modified which is unlikely. I propose to use "hannstar,hsd101pww1" which is more wide spread.