Messages in this thread | | | Date | Tue, 4 Jan 2011 17:05:33 -0800 | From | Andrew Morton <> | Subject | Re: [BUG] VGA palette corruption in vgacon.c for EFI machine |
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On Fri, 26 Nov 2010 09:44:51 -0500 Yannick Heneault <yannick_heneault@matrox.com> wrote:
> Hi, > > It seems there is a small problem of VGA palette corruption on EFI > machine. When the kernel initializes the architecture, it checks if the > machine is a EFI machine and if the memory at 0xa0000 is not tagged as > conventional memory, which should not be the case because this is VGA > memory. In that case, the kernel assumes that a VGA console can exist. I > would think that this assumption is correct. > > When the kernel initialize the console in vgacon_startup it checks if it > can really use the VGA console. I think this is where a check is > missing. Currently, the function can fail if a VESA boot mode is > detected but not if a EFI boot mode was used. I think the code should be > modified like this : > > --- a/drivers/video/console/vgacon.c > +++ b/drivers/video/console/vgacon.c > @@ -377,7 +377,8 @@ static const char *vgacon_startup(void) > u16 saved1, saved2; > volatile u16 *p; > > - if (screen_info.orig_video_isVGA == VIDEO_TYPE_VLFB) { > + if (screen_info.orig_video_isVGA == VIDEO_TYPE_VLFB || > + screen_info.orig_video_isVGA == VIDEO_TYPE_EFI) { > no_vga: > #ifdef CONFIG_DUMMY_CONSOLE > conswitchp = &dummy_con; > > > In that case, the VGA console will fail and a dummy console will be > temporary used until the EFI driver get loaded. At that point the > console will be mapped to the EFI driver and graphics (splash screen and > penguins) will appear correctly. > > Currently, the function vgacon_startup doesn't fail and initialize the > video card for a real VGA mode. This function change the first 16 > entries of the VGA palette. When the efifb driver kick-in, the palette > is not restored to default ramp value, thus the 16 first entry remain in > a modified state. >
If that fix worked for you then please send it as a formal, tested, signed-off kernel patch and we'll put it in the pipeline and see what emerges from the other end.
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