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

[Marijn Suijten]

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.

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