[Mesa-dev] [PATCH] egl/android: Partially handle HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED

[Rob Herring]

On Tue, Nov 28, 2017 at 8:42 AM, Tomasz Figa <tfiga at chromium.org> wrote:
> On Tue, Nov 28, 2017 at 11:27 PM, Rob Herring <robh at kernel.org> wrote:
>> On Tue, Nov 28, 2017 at 5:49 AM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
>>> On 28 November 2017 at 10:45, Tapani Pälli <tapani.palli at intel.com> wrote:
>>>> Hi;
>>>>
>>>>
>>>> On 11/27/2017 04:14 PM, Robert Foss wrote:
>>
>> [...]
>>
>>>>> +   /* HACK: See droid_create_image_from_prime_fd() and b/32077885. */
>>>>> +   { HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED,   0, 2,
>>>>> __DRI_IMAGE_FOURCC_NV12 },
>>>>> +   { HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED,   0, 1,
>>>>> __DRI_IMAGE_FOURCC_YUV420 },
>>>>> +   { HAL_PIXEL_FORMAT_IMPLEMENTATION_DEFINED,   1, 1,
>>>>> __DRI_IMAGE_FOURCC_YVU420 },
>>>>
>>>>
>>>> One alternative way would be to ask gralloc about these formats. On gralloc0
>>>> this would need a perform() hook and gralloc1 has getFormat(). This is how
>>>> it is done currently on Android-IA, see following commits:
>>>>
>>>> https://github.com/intel/external-mesa/commit/deb323eafa321c725805a702ed19cb4983346b60
>>>>
>>>> https://github.com/intel/external-mesa/commit/7cc01beaf540e29862853561ef93c6c4e86c4c1a
>>>>
>>>> Do you think this approach would work with Chromium as well?
>>>>
>>> i think the Android-IA approach looks good, although it depends on
>>> local gralloc0 changes. With gralloc1 on the horizon, I don't know how
>>> much sense it makes to extend the predecessor.
>>> AFAICT the patch should not cause any issues and it's nicely documented.
>>>
>>> Perhaps someone from the Google/CrOS team can assist in making the bug
>>> public, although even then it might be better to focus on a 'perfect'
>>> gralloc1?
>>>
>>> IMHO the patch looks perfectly reasonable and we could merge it even,
>>> if we were to switch to gralloc1 in the not too distant future ;-)
>>
>> gralloc1 has already come and gone. The interface is now (in O+)
>> IAllocator and IMapper aka gralloc 2.0.
>
> Oh, that was a new one for me. Do you have any idea about real world
> adoption of this interface? We're still using gralloc0 in Chrome OS
> Android.

Pretty sure everyone else is too and will be until something forces
them to move. Maybe P will be stricter and not allow pass-thru
implementations (though I don't see how you could ever binderize
mmap).

>> There is neither perform nor
>> getFormat(). Seemed to me gralloc1 was moving in the right direction,
>> but I guess making cross process calls to retrieve buffer metadata was
>> not a good design. Other than standardizing the native_handle_t
>> fields, I'm not sure how one would solve this in a gralloc2 world.
>
> Well, the ideal solution would be to extend IMapper in next version of
> the interface to have a method that gives us the data we need.

Vendors can extend interfaces. AIUI, the rule is the HALs have to work
with stock AOSP without the extensions.

> If not, one could still do some hacks like a library exporting some
> semi-standard functions which take a handle as an argument and provide
> the data we need as a result.

You can still have private interfaces amongst vendor components. We
can also just standardize how we sub-class the native_handle. That was
my intention with moving it from gralloc to drm_hwc. We can debate
whether we expose the struct or helper functions.

Rob