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    SubjectRe: [Freedreno] [PATCH v3 06/10] drm/msm/dsi: Migrate to drm_dsc_compute_rc_parameters()


    On 17/10/2022 09:59, Marijn Suijten wrote:
    > On 2022-10-13 09:02:44, Abhinav Kumar wrote:
    >> On 10/13/2022 2:36 AM, Marijn Suijten wrote:
    >>> On 2022-10-12 16:03:06, Abhinav Kumar wrote:
    >>>> [..]
    >>>> But I would like to hold back this change till Vinod clarifies because
    >>>> Vinod had mentioned that with drm_dsc_compute_rc_parameters() he was
    >>>> seeing a mismatch in the computation of two values.
    >>>>
    >>>> slice_bpg_offset and the final_offset.
    >>>
    >>> Unsurprisingly so because final_offset, and slice_bpg_offset through
    >>> initial_offset depend directly on bits_per_pixel. The main takeaway of
    >>> this series is that Vinod was interpreting this field as integer instead
    >>> of containing 4 fractional bits. If he updates his the panel driver [1]
    >>> to set bits_per_pixel = 8 << 4 instead of just 8 to account for this,
    >>> the values should check out once again.
    >>>
    >>> [1]: https://git.linaro.org/people/vinod.koul/kernel.git/commit/?h=topic/pixel3_5.18-rc1&id=1d7d98ad564f1ec69e7525e07418918d90f247a1
    >>>
    >>> Once Vinod (or someone else in the posession of a Pixel 3) confirms
    >>> this, I can respin this series and more explicitly explain why the FIXME
    >>> was put in place, instead of being resolved outright?
    >>>
    >>> - Marijn
    >>
    >> Makes perfect sense to me.
    >>
    >> Will just wait for Vinod's tested-by.
    >
    > Unfortunately Vinod doesn't have access to this device anymore, but
    > Caleb recently sent the support series including display driver for
    > Pixel 3 and is picking up the testing. User "Newbyte" from #linux-msm
    > promised to test on the LG G7 to have even more input samples.

    Hi,

    I'm hoping to pick the Pixel 3 stuff back up at some point, but right now there
    seem to be quite a few issues outside of DSC which make testing it a bit of a pain.

    I gave Marijn's series [1] a go but wasn't able to get anything usable out of the
    panel, however I doubt this is a DSC issue as I've always needed some hacks to
    get the panel working - I've never had any success with it without skipping both
    the initial panel reset and sending the PPS payload.

    I think if Marijn has managed to initialise a panel properly then the lack of
    Pixel 3 for validation shouldn't be a blocker to merge these fixes.

    [1]:
    https://lore.kernel.org/linux-arm-msm/20221009184824.457416-1-marijn.suijten@somainline.org/

    >
    > - Marijn

    --
    Kind Regards,
    Caleb

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