[RESEND PATCH 2/2] modetest: only select plane with matching format

Tobias Jakobi tjakobi at math.uni-bielefeld.de
Thu Jun 11 06:43:48 PDT 2015

Sorry for the late reply!

On 2015-05-28 14:25, Emil Velikov wrote:
>> If you
>> create your primary plane with a XRGB-type format then this patch
>> doesn't change anything. If you create it with an ARGB-type format 
>> then
>> I can assume that the user wants an alpha-channel (he explicitly asks
>> for it).
> True. But the test might be assuming that alpha is always 255, thus it
> expects that the output for XRGB and ARGB type formats is the same.
I still don't understand this part at all. What "test" are we actually 
talking about? Do you mean some test application that somehow internally 
uses output from libdrm's modetest? I have trouble seeing how this 
should work at all? If this patch changes anything then it's visual 
output on the screen (assuming that the DRM driver somehow interprets 
the content of the 'X' channel). So only something that a human 
inspecting the screen could detect.

Or am I missing something here?

> Obviously the likely-hood of all that is negligible, esp. considering
> the benefit that the patch brings.
> I'm picking libdrm patches off the list as we speak, which will include
> both of these.
> Thanks
> Emil

With best wishes,

More information about the dri-devel mailing list