[PATCH 3/5] drm/udl: Add GEM object functions for free(), vmap(), and vunmap()

[Thomas Zimmermann]

Hi

Am 25.10.19 um 15:32 schrieb Gerd Hoffmann:
>   Hi,
> 
>>> I had a flag to set this in the initial version of the shmem helper
>>> modeled after udl, but Thomas Hellstrom brought up a question and it was
>>> dropped. The issue was beyond my understanding:
>>>
>>> [PATCH v3 0/2] drm: Add shmem GEM library
>>> https://lists.freedesktop.org/archives/dri-devel/2018-September/190001.html
>>
>> If I understand that discussion correctly, the concern was that write
>> combining and shared memory would not work well together. So you went
>> with always-cached?
>>
>> Just recently, Gerd added unconditional write combining in rev 0be8958936.
> 
> Well, it's not really added.  It's the same thing drm_gem_mmap_obj()
> does for you when you don't have a drm_gem_object_funcs.mmap callback.
> 
> But, yes, the reason this is done in the driver's mmap() callback with
> the new mmap code path is to give drivers the option to override this
> by supplying their own mmap() handler.  So going with shmem helpers +
> custom mmap callback is a reasonable approach.
> 
> HTH,

Absolutely.

Thanks everyone for the feedback.

Best regards
Thomas

>   Gerd
> 
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> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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