[Nouveau] [PATCH] bios: fix OF loading

[Ilia Mirkin]

On Fri, Oct 2, 2015 at 3:35 AM, Hans de Goede <hdegoede at redhat.com> wrote:
> Hi,
>
> On 02-10-15 09:26, Ilia Mirkin wrote:
>>
>> On Fri, Oct 2, 2015 at 3:18 AM, Hans de Goede <hdegoede at redhat.com> wrote:
>>>
>>> Hi,
>>>
>>> On 02-10-15 05:41, Ilia Mirkin wrote:
>>>
>>> <nothing>
>>>
>>> As someone who has recently started following nouveau I must say that
>>> it would greatly help me (and likely others) if patches likes this would
>>> come with a somewhat more descriptive commit message.
>>
>>
>> Duly noted. I normally try to say a bit, but have gotten lazy of late.
>> Ben's pretty terse too :) How about something like
>>
>> """
>> Currently OF bios load fails for a few reasons:
>>   - checksum failure
>>   - bios size too small
>>   - no PCIR header
>>   - bios length not a multiple of 4
>>
>> In this change, we resolve all of the above by ignoring any checksum
>> failures, and faking the PCIR data when loading from OF.
>> """
>
>
> Much better, I must say that now that you spell it out that the
> ignoring of the checksum sort of worries me, but I guess the
> checksum is part of the missing PCIR header ?

Nope, the two things are unrelated. The PCIR section is normally
embedded in the vbios and tells you how long the vbios is, and allows
you to have multiple elements appended at the end (which nouveau has
recently acquired some support for). The checksum failures just
happen, pretty sure that the OF-sourced vbioses just don't have a
checksum byte at all. And they cause nouveau to try to load a vbios
from a different source, which almost invariably fails to actually
parse properly. (Why? Because you should just use the one from OF,
duh!)

  -ilia