[Mesa-dev] [PATCH] r600g: Fix ARB_texture_rgb10_a2ui support in big-endian

[Oded Gabbay]

On Mon, Feb 29, 2016 at 7:44 AM, Ilia Mirkin <imirkin at alum.mit.edu> wrote:
> On Mon, Feb 29, 2016 at 12:31 AM, Oded Gabbay <oded.gabbay at gmail.com> wrote:
>> On Mon, Feb 29, 2016 at 3:51 AM, Michel Dänzer <michel at daenzer.net> wrote:
>>> On 28.02.2016 05:48, Oded Gabbay wrote:
>>>> This patch enables the correct detection of PIPE_FORMAT_R10G10B10A2_UINT
>>>> and PIPE_FORMAT_B10G10R10A2_UINT formats in r600g in big-endian mode, by
>>>> adjusting the order of channels in various functions.
>>>>
>>>> This enables support for ARB_texture_rgb10_a2ui, which otherwise is not
>>>> detected as supported.
>>>>
>>>> Signed-off-by: Oded Gabbay <oded.gabbay at gmail.com>
>>>> ---
>>>>  src/gallium/drivers/r600/r600_state_common.c | 15 ++++++++++-----
>>>>  1 file changed, 10 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/src/gallium/drivers/r600/r600_state_common.c b/src/gallium/drivers/r600/r600_state_common.c
>>>> index b231d1e..b02b6a9 100644
>>>> --- a/src/gallium/drivers/r600/r600_state_common.c
>>>> +++ b/src/gallium/drivers/r600/r600_state_common.c
>>>> @@ -2468,10 +2468,13 @@ uint32_t r600_translate_texformat(struct pipe_screen *screen,
>>>>                               result = FMT_1_5_5_5;
>>>>                               goto out_word4;
>>>>                       }
>>>> -                     if (desc->channel[0].size == 10 &&
>>>> -                         desc->channel[1].size == 10 &&
>>>> -                         desc->channel[2].size == 10 &&
>>>> -                         desc->channel[3].size == 2) {
>>>> +                     if ((desc->channel[1].size == 10 &&
>>>> +                               desc->channel[2].size == 10) &&
>>>> +                                     ((desc->channel[0].size == 10 &&
>>>> +                                       desc->channel[3].size == 2) ||
>>>> +                                      (R600_BIG_ENDIAN &&
>>>> +                                       desc->channel[0].size == 2 &&
>>>> +                                       desc->channel[3].size == 10))) {
>>>>                               result = FMT_2_10_10_10;
>>>>                               goto out_word4;
>>>>                       }
>>>> @@ -2694,9 +2697,11 @@ uint32_t r600_translate_colorformat(enum chip_class chip, enum pipe_format forma
>>>>                       }
>>>>               } else if (HAS_SIZE(5,5,5,1)) {
>>>>                       return V_0280A0_COLOR_1_5_5_5;
>>>> -             } else if (HAS_SIZE(10,10,10,2)) {
>>>> +             } else if (HAS_SIZE(10,10,10,2) ||
>>>> +                             (R600_BIG_ENDIAN && HAS_SIZE(2,10,10,10))) {
>>>
>>> Since the components of these formats cross byte boundaries, these
>>> formats should really be treated as packed by the core Gallium code, in
>>> which case this change probably wouldn't be necessary. In other words,
>>> this is probably working around a core Gallium bug.
>>>
>>
>> so ?
>
> I think the point here is that RGB10A2 in LE != A2BGR10 in BE. They're
> both packed integer formats, and the byteswapping that happens between
> LE/BE does not happen on component boundaries. So there's no way this
> works, and if it does, it's purely by luck. Instead of breaking this
> spot, fix the other spot where it's currently broken.
>
>   -ilia

Thanks Michel & Ilia,

I'll investigate it and get back with a new patch.

Oded