[Intel-gfx] [PATCH v2 1/3] drm: Add the optional .fb_modifier() hook

Michel Dänzer michel at daenzer.net
Tue Mar 13 15:18:50 UTC 2018

On 2018-03-13 04:12 PM, Ville Syrjälä wrote:
> On Tue, Mar 13, 2018 at 03:38:38PM +0100, Michel Dänzer wrote:
>> On 2018-03-13 03:28 PM, Ville Syrjala wrote:
>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>> To make it possible for the core to check the fb pixel format and
>>> modifier, we need to first ask the driver to deduce the modifier
>>> when the request does not explicitly specify one.
>>> Add a new .fb_modifier() hook for that purpose and convert i915
>>> and vc4 to make use if it. All other drivers seem to currently
>>> assume linear when the request does not specify anything else,
>>> [...]
>> That's not true at least for the amdgpu and radeon drivers. The tiling
>> mode is communicated via BO metadata.
> Well, at least those driver don't do any bo tiling->modifier conversion.
> Radeon doesn't do modifiers I suppose, so that part is probably OK.
> amggpu might just be broken, not sure.

amdgpu certainly wasn't broken before modifiers came along. If something
broke with those, I'd say it's more accurate to say that's broken and
needs to be fixed, rather than adding more incorrect assumptions based
on it.

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

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