Framebuffer drivers that break the boot on systemswithout the hardware

Framebuffer drivers that break the boot on systemswithout the hardware

[Rene Herman]

Hi Antonino.

At:

http://lkml.org/lkml/2008/8/1/96

Ingo Molnar posted a list of drivers he found to break the boot during 
testing of randconfig kernels and among them are a number of FB drivers:

   FB_CIRRUS
   FB_ASILIANT
   FB_VGA16
   FB_VESA
   FB_RADEON
   FB_CYBLA
   (and FB_VIRTUAL)

Looking at some of them there wouldn't seem to be too many very sensible 
options to avoid this at the individual driver level. Would you perhaps 
have an idea how to avoid the issue generically for these?

More of the drivers in that list will  be considered fine as is but I 
was fixing some of the old legacy ISA ones as ofcourse any driver not 
needing special avoidance treatment is one less to have to deal with.

The randconfig testing IS useful in finding bugs, so...

Rene.

Re: Framebuffer drivers that break the boot on systemswithout the hardware

[Frans Pop]

Rene Herman wrote:
> Ingo Molnar posted a list of drivers he found to break the boot during
> testing of randconfig kernels and among them are a number of FB drivers:
> 
> FB_VESA

This one is set to "y" in the kernel configs for the generic Debian 
kernels for i386 and x86_64 and is used by default for the graphical 
version of the Debian Installer, so I'd be very surprised if it broke 
very many systems...
AFAIK it is only actually enabled if the 'vga=' boot parameter is passed.

Ingo's mail also lists FRAMEBUFFER_CONSOLE which again is set to "y" in 
Debian's standard kernel configs for x86 (and probably most other 
arches).

> (and FB_VIRTUAL)

This one should be fixed with 2.6.27-rc1. The commit that fixes it is:
  commit b604838ac6d233fd6bffc0e758a818133a01ff22
  Author: Frans Pop <elendil@planet.nl>
  Date:   Wed Jul 23 21:31:26 2008 -0700
    vfb: only enable if explicitly requested when compiled in

Cheers,
FJP

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Re: Framebuffer drivers that break the boot on systemswithout the hardware

[Rene Herman]

On 09-08-08 23:19, Frans Pop wrote:

> Rene Herman wrote:

>> Ingo Molnar posted a list of drivers he found to break the boot during
>> testing of randconfig kernels and among them are a number of FB drivers:
>>
>> FB_VESA
> 
> This one is set to "y" in the kernel configs for the generic Debian 
> kernels for i386 and x86_64 and is used by default for the graphical 
> version of the Debian Installer, so I'd be very surprised if it broke 
> very many systems...
> AFAIK it is only actually enabled if the 'vga=' boot parameter is passed.
> 
> Ingo's mail also lists FRAMEBUFFER_CONSOLE which again is set to "y" in 
> Debian's standard kernel configs for x86 (and probably most other 
> arches).

Okay. MDA_CONSOLE was also in there impying RAM at 0xb0000 which might 
indicate a gun/foot situation here...

>> (and FB_VIRTUAL)
> 
> This one should be fixed with 2.6.27-rc1. The commit that fixes it is:
>   commit b604838ac6d233fd6bffc0e758a818133a01ff22
>   Author: Frans Pop <elendil@planet.nl>
>   Date:   Wed Jul 23 21:31:26 2008 -0700
>     vfb: only enable if explicitly requested when compiled in

Ah, thanks.

Rene.


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