[PATCH] efifb: dmi set video type

[PATCH] efifb: dmi set video type

[Brian Maly]

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The current logic for dmi matching in efifb does not allow efifb to load 
on all hardware that we can dmi match for.

For a real world example, boot with elilo (3.7 or 3.8 vanilla) and on a 
Apple (MacBook) and EFI framebuffer driver will not load (you will have 
no video).
This specific hardware is efi v1.10, so we have UGA and not GOP. Without 
special bootloader magic (i.e. extra elilo patches for UGA graphics 
detection) no screen info will be passed to the kernel and as a result 
efifb will not load.

This patch allows the dmi match to happen by moving it to earlier in 
efifb_init, and sets the video type (in set_system) so that efifb can 
load when we have a valid dmi match and already know the specifics of 
the hardware.

Without this patch the efifb driver will fail to load in the event 
screen info is not found and passed in by the bootloader, being that we 
will never get to look for a dmi match. A primary reason for matching 
with dmi is because not all bootloaders detect the video info properly. 
The solution is that in the event of a dmi match, we should set 
screen_info.orig_video_isVGA. Most bootloaders fail to set screen info 
on Apple hardware, and this is a big problem for people who use Apple 
hardware.

Tested on a MacBook SantaRosa with elilo-3.8 (vanilla) and resolves the 
issue, the dmi match now works, EFI framebuffer now loads and video works.


Signed-off-by: Brian Maly <bmaly@redhat>



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--- a/drivers/video/efifb.c	2009-03-21 21:05:08.000000000 -0400
+++ b/drivers/video/efifb.c	2009-03-21 21:16:20.000000000 -0400
@@ -129,6 +129,8 @@ static int set_system(const struct dmi_s
 		screen_info.lfb_width = info->width;
 	if (screen_info.lfb_height == 0)
 		screen_info.lfb_height = info->height;
+	if (screen_info.orig_video_isVGA == 0)
+		screen_info.orig_video_isVGA = VIDEO_TYPE_EFI;
 
 	return 0;
 }
@@ -374,9 +376,10 @@ static int __init efifb_init(void)
 	int ret;
 	char *option = NULL;
 
+	dmi_check_system(dmi_system_table);
+
 	if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI)
 		return -ENODEV;
-	dmi_check_system(dmi_system_table);
 
 	if (fb_get_options("efifb", &option))
 		return -ENODEV;

Re: [PATCH] efifb: dmi set video type

[Huang Ying]

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Hi, Brian,

The patch is OK for me.

Please cc linux-fbdev-devel@lists.sourceforge.net and "Antonino A.
Daplas" <adaplas@pol.net> on framebuffer driver patches.

Best Regards,
Huang Ying

On Sun, 2009-03-22 at 06:16 +0800, Brian Maly wrote:
> The current logic for dmi matching in efifb does not allow efifb to load 
> on all hardware that we can dmi match for.
> 
> For a real world example, boot with elilo (3.7 or 3.8 vanilla) and on a 
> Apple (MacBook) and EFI framebuffer driver will not load (you will have 
> no video).
> This specific hardware is efi v1.10, so we have UGA and not GOP. Without 
> special bootloader magic (i.e. extra elilo patches for UGA graphics 
> detection) no screen info will be passed to the kernel and as a result 
> efifb will not load.
> 
> This patch allows the dmi match to happen by moving it to earlier in 
> efifb_init, and sets the video type (in set_system) so that efifb can 
> load when we have a valid dmi match and already know the specifics of 
> the hardware.
> 
> Without this patch the efifb driver will fail to load in the event 
> screen info is not found and passed in by the bootloader, being that we 
> will never get to look for a dmi match. A primary reason for matching 
> with dmi is because not all bootloaders detect the video info properly. 
> The solution is that in the event of a dmi match, we should set 
> screen_info.orig_video_isVGA. Most bootloaders fail to set screen info 
> on Apple hardware, and this is a big problem for people who use Apple 
> hardware.
> 
> Tested on a MacBook SantaRosa with elilo-3.8 (vanilla) and resolves the 
> issue, the dmi match now works, EFI framebuffer now loads and video works.
> 
> 
> Signed-off-by: Brian Maly <bmaly@redhat>
> 
> 

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