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

[Abhinav Kumar]

On 6/22/2023 11:57 PM, Marijn Suijten wrote:
> On 2023-06-23 08:54:39, 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.
> 
> Ah, as expected Dmitry's second commit clarifies that the last register
> in the enc block is at 0x98, and the base of the enc + length of the enc
> then is 0x200 + 0x9c.
> 
> That still excludes the ctl sblk.

0x29c is not an arbitrary number. The last encoder offset is 0x298 so we 
add 4 more to that.

Yes it will still exclude ctl blk as that space is not contiguous and we 
dont want to increase len all the way to 0xf00.

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