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apple-gmux: Fixes related to 'Support for new hardware'

PATCH In review Bernhard Froemel 3 participants 6 messages Aug 25, 2012 – Aug 26, 2012 x86 platform drivers

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Bernhard Froemel

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#0 lore raw

v2 cover apple-gmux: Fixes related to 'Support for new hardware'

Hello,

it follows a refined version where thanks to Seth and his extensive x86 assembly knowledge my initial assumption about how Apple does byte writes could be falsified. It appears that byte writes only failed because the index protocol was not correctly followed in the read functions.

Cheers,
Bernhard

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#1 lore raw

PATCH v2 1/2 apple-gmux: Fix index read functions

From: Bernhard Froemel <[email protected]>

Study of Apple's binary driver revealed that the GMUX_READ_PORT should be written between calls to gmux_index_wait_ready and gmux_index_wait_complete (i.e., the new index protocol must be followed). If this is not done correctly, the indexed
gmux device only partially accepts writes which lead to problems concerning GPU switching. Special thanks to Seth Forshee who helped greatly with identifying unnecessary changes.

Signed-off-by Bernhard Froemel <[email protected]>
---
 drivers/platform/x86/apple-gmux.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)
drivers/platform/x86/apple-gmux.c +4 -2
index dfb1a92..c38538e 100644
@@ -142,8 +142,9 @@ static u8 gmux_index_read8(struct apple_gmux_data *gmux_data, int port)
 	u8 val;
 
 	mutex_lock(&gmux_data->index_lock);
-	outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
 	gmux_index_wait_ready(gmux_data);
+	outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
+	gmux_index_wait_complete(gmux_data);
 	val = inb(gmux_data->iostart + GMUX_PORT_VALUE);
 	mutex_unlock(&gmux_data->index_lock);
 

@@ -166,8 +167,9 @@ static u32 gmux_index_read32(struct apple_gmux_data *gmux_data, int port)
 	u32 val;
 
 	mutex_lock(&gmux_data->index_lock);
-	outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
 	gmux_index_wait_ready(gmux_data);
+	outb((port & 0xff), gmux_data->iostart + GMUX_PORT_READ);
+	gmux_index_wait_complete(gmux_data);
 	val = inl(gmux_data->iostart + GMUX_PORT_VALUE);
 	mutex_unlock(&gmux_data->index_lock);
Signature · 1 line
1.7.9.5
author
#2 lore raw

PATCH v2 2/2 apple-gmux: Obtain version info from indexed gmux

From: Bernhard Froemel <[email protected]>

This patch extracts and displays version information from the indexed gmux device as it is also done for the classic gmux device.

Signed-off-by Bernhard Froemel <[email protected]>
---
 drivers/platform/x86/apple-gmux.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
drivers/platform/x86/apple-gmux.c +8 -4
index c38538e..0e43477 100644
@@ -463,18 +463,22 @@ static int __devinit gmux_probe(struct pnp_dev *pnp,
 	ver_release = gmux_read8(gmux_data, GMUX_PORT_VERSION_RELEASE);
 	if (ver_major == 0xff && ver_minor == 0xff && ver_release == 0xff) {
 		if (gmux_is_indexed(gmux_data)) {
+			u32 version;
 			mutex_init(&gmux_data->index_lock);
 			gmux_data->indexed = true;
+			version = gmux_read32(gmux_data,
+				GMUX_PORT_VERSION_MAJOR);
+			ver_major = (version >> 24) & 0xff;
+			ver_minor = (version >> 16) & 0xff;
+			ver_release = (version >> 8) & 0xff;
 		} else {
 			pr_info("gmux device not present\n");
 			ret = -ENODEV;
 			goto err_release;
 		}
-		pr_info("Found indexed gmux\n");
-	} else {
-		pr_info("Found gmux version %d.%d.%d\n", ver_major, ver_minor,
-			ver_release);
 	}
+	pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major, ver_minor,
+		ver_release, (gmux_data->indexed ? "indexed" : "classic"));
 
 	memset(&props, 0, sizeof(props));
 	props.type = BACKLIGHT_PLATFORM;
Signature · 1 line
1.7.9.5
Tested-by on v2 1/2
#4 lore raw

Re: [PATCH v2 1/2] apple-gmux: Fix index read functions

In reply to Bernhard Froemel
Quoted 10 lines · Bernhard Froemel

From: Bernhard Froemel <[email protected]>

Study of Apple's binary driver revealed that the GMUX_READ_PORT should be written between calls to gmux_index_wait_ready and gmux_index_wait_complete (i.e., the new index protocol must be followed). If this is not done correctly, the indexed
gmux device only partially accepts writes which lead to problems concerning GPU switching. Special thanks to Seth Forshee who helped greatly with identifying unnecessary changes.

Quoted 2 lines
Signed-off-by Bernhard Froemel <[email protected]>

---

Hi Bernhard,

thanks for your patch, this works splendidly; I can resume and select different screen resolutions using xrandr.

Tested-by Henrik Rydberg <[email protected]>

Henrik

Acked-by on v2 1/2
#5 lore raw

Re: [PATCH v2 1/2] apple-gmux: Fix index read functions

In reply to Bernhard Froemel
Quoted 11 lines · Bernhard Froemel

From: Bernhard Froemel <[email protected]>

Study of Apple's binary driver revealed that the GMUX_READ_PORT should be written between calls to gmux_index_wait_ready and gmux_index_wait_complete (i.e., the new index protocol must be followed). If this is not done correctly, the indexed
gmux device only partially accepts writes which lead to problems concerning GPU switching. Special thanks to Seth Forshee who helped greatly with identifying unnecessary changes.

Signed-off-by Bernhard Froemel <[email protected]>

This does better match what Apple's driver does. Thanks Bernhard.

Acked-by Seth Forshee <[email protected]>