[PATCH 1/2] drm/msm/dpu: fix DSC 1.2 block lengths

[Dmitry Baryshkov]

On 23/06/2023 09:54, Marijn Suijten wrote:
> On 2023-06-22 22:47:04, Abhinav Kumar wrote:
>> On 6/22/2023 6:37 PM, Dmitry Baryshkov wrote:
>>> All DSC_BLK_1_2 declarations incorrectly pass 0x29c as the block length.
>>> This includes the common block itself, enc subblocks and some empty
>>> space around. Change that to pass 0x4 instead, the length of common
>>> register block itself.
>>>
>>> Fixes: 0d1b10c63346 ("drm/msm/dpu: add DSC 1.2 hw blocks for relevant chipsets")
>>> Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov at linaro.org>
>>
>> There is no need of a fixes tag for this.
>>
>> This is not a bug but was intentional.
>>
>> Till we added sub-block parsing support we had to dump the whole block.
>>
>> And hence I would suggest this change should be merged after the
>> sub-block parsing change otherwise we wont have full register dumps for DSC.
> 
> This was indeed intentional, we discussed it in [1].
> 
> In fact I asked to make it 0xf00 + 0x10 or 0xf80 + 0x10 to also cover
> the CTL registers, but that change didn't make it through.  0x29c is an
> arbitrary number that I have no clue what it was based on.

This should have been NAKed. or at least TODOed.

> 
> [1]: https://lore.kernel.org/linux-arm-msm/y2whfntyo2rbrg3taazjdw5sijle6k6swzl4uutcxm6tmuayh4@uxdur74uasua/
> 
> - Marijn

-- 
With best wishes
Dmitry