[PATCH libdrm] xf86drm: Parse the separate files to retrieve the vendor/device info

[Michel Dänzer]

On 07/11/16 08:30 PM, Emil Velikov wrote:
> On 7 November 2016 at 09:14, Michel Dänzer <michel at daenzer.net> wrote:
>> On 05/11/16 03:14 AM, Emil Velikov wrote:
>>> On 2 November 2016 at 03:07, Michel Dänzer <michel at daenzer.net> wrote:
>>>>
>>>> The first attached patch will result in drmParsePciDeviceInfo always
>>>> reporting revision 0 on kernels without the second attached patch. Will
>>>> that be an issue for the amdgpu-pro stack?
>>>>
>>>> Please follow up directly to the patch e-mails with any comments on the
>>>> patches.
>>>>
>>> Fleshing out the question from the actual patches:
>>>
>>> Do the AMDGPU-PRO or the AMD stack [as a whole] depend on the revision
>>> field as returned by the drmDevice API ?
>>
>> One answer is that https://patchwork.freedesktop.org/patch/120132/ uses
>> the revision ID. In this case a wrong revision ID would only cause a
>> cosmetic issue, but I can imagine that other code in the amdgpu-pro
>> stack really needs the correct revision ID to accurately identify the GPU.
>>
> Don't mean to sound rude, but I was hoping for a definite answer.

So was I. :}

Digging further, the above patch actually doesn't use the revision_id
field but amdgpu kernel driver functionality to determine the revision.
Given that such functionality exists, I don't think we have do any more
special consideration of either amdgpu stack.


> Regardless, do you/fellow AMD devs, any preference on how to go with
> this bug [1] ?
> 
> Add an override to force use of the revision file - be that envvar,
> new API {drmDeviceUseRevisionFile, drmDevice...v2}, or revert the 12 +
> commits (pulling only the offending one won't cut it). Obviously I'm
> not a huge fan of the last one :-\
> 
> [1] https://bugs.freedesktop.org/show_bug.cgi?id=98502

I'm afraid I don't have any particularly strong opinion to offer here.
But it seems weird to me to have an API which pretends to provide the
revision ID, but it can actually be incorrect. (The same would apply to
any other information, not just the revision ID in particular)


-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer