Skip to contentSkip to conversation

drm/fb: Propagate physical display dimensions to fbdev

RFC In review David Lechner 2 participants 2 messages Jul 30, 2017 – Jul 31, 2017

Subsystems (2)
lore
Share & tools
lore
#0 lore raw

RFC 1/1 drm/fb: Propagate physical display dimensions to fbdev

fbdev has a place for the physical width and height of a display. I would like to have this information available to userspace. This patch works for me, but I have a strong suspicion that this is not the "right way".

Any suggestions on how to get the proper struct drm_display_info here rather than assuming the first connector one is valid? I don't see an obvious way to do this.

---
 drivers/gpu/drm/drm_fb_helper.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
drivers/gpu/drm/drm_fb_helper.c +8 -2
index 574af01..ff422da 100644
@@ -1768,8 +1768,14 @@ void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helpe
 	info->var.xoffset = 0;
 	info->var.yoffset = 0;
 	info->var.activate = FB_ACTIVATE_NOW;
-	info->var.height = -1;
-	info->var.width = -1;
+
+	if (fb_helper->connector_count) {
+		info->var.height = fb_helper->connector_info[0]->connector->display_info.width_mm;
+		info->var.width = fb_helper->connector_info[0]->connector->display_info.height_mm;
+	} else {
+		info->var.height = -1;
+		info->var.width = -1;
+	}
 
 	switch (fb->format->depth) {
 	case 8:
Signature · 1 line
2.7.4
#1 lore raw
Quoted 8 lines

Sun, Jul 30, 2017 at 11:11 PM, David Lechner <[email protected]> wrote:
fbdev has a place for the physical width and height of a display. I would like to have this information available to userspace. This patch works for me, but I have a strong suspicion that this is not the "right way".

Any suggestions on how to get the proper struct drm_display_info here rather than assuming the first connector one is valid? I don't see an obvious way to do this.

This data can also change at runtime, which means we need to reprobe it. And as you mention, we need to pick the data of the first connected connector, not the very first connector the driver has. The final connector loo in drm_setup_crtcs() would be a good place to do that I think.
-Daniel

Quoted 32 lines
---
 drivers/gpu/drm/drm_fb_helper.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)
drivers/gpu/drm/drm_fb_helper.c +8 -3
index 574af01..ff422da 100644
@@ -1768,8 +1768,14 @@ void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helpe
        info->var.xoffset = 0;
        info->var.yoffset = 0;
        info->var.activate = FB_ACTIVATE_NOW;
-       info->var.height = -1;
-       info->var.width = -1;
+
+       if (fb_helper->connector_count) {
+               info->var.height = fb_helper->connector_info[0]->connector->display_info.width_mm;
+               info->var.width = fb_helper->connector_info[0]->connector->display_info.height_mm;
+       } else {
+               info->var.height = -1;
+               info->var.width = -1;
+       }
 
        switch (fb->format->depth) {
        case 8:
--

2.7.4

_______________________________________________
dri-devel mailing list
[email protected]
https://lists.freedesktop.org/mailman/listinfo/dri-devel

Signature · 3 lines
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch