[PATCH v2] drm/msm/dpu: always program dsc active bits

[Dmitry Baryshkov]

On Fri, 14 Apr 2023 at 21:55, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>
>
>
> On 4/14/2023 10:28 AM, Marijn Suijten wrote:
> > On 2023-04-14 08:41:37, Abhinav Kumar wrote:
> >>
> >> On 4/14/2023 12:48 AM, Marijn Suijten wrote:
> >>> Capitalize DSC in the title, as discussed in v1.
> >>>
> >>> On 2023-04-13 08:56:41, Kuogee Hsieh wrote:
> >>>> In current code, the DSC active bits are written only if cfg->dsc is set.
> >>>> However, for displays which are hot-pluggable, there can be a use-case
> >>>> of disconnecting a DSC supported sink and connecting a non-DSC sink.
> >>>>
> >>>> For those cases we need to clear DSC active bits during tear down.
> >>>>
> >>>> Changes in V2:
> >>>> 1) correct commit text as suggested
> >>>> 2) correct Fixes commit id
> >>>> 3) add FIXME comment
> >>>>
> >>>> Fixes: 77f6da90487c ("drm/msm/disp/dpu1: Add DSC support in hw_ctl")
> >>>> Signed-off-by: Kuogee Hsieh <quic_khsieh at quicinc.com>
> >>>> Reviewed-by: Marijn Suijten <marijn.suijten at somainline.org>
> >>>
> >>> By default git send-email should pick this up in the CC line...  but I
> >>> had to download this patch from lore once again.
> >>>
> >>
> >> Yes, I think what happened here is, he didnt git am the prev rev and
> >> make changes on top of that so git send-email didnt pick up. We should
> >> fix that process.
> >
> > The mail was sent so it must have gone through git send-email, unless a
> > different mail client was used to send the .patch file.  I think you are
> > confusing this with git am (which doesn't need to be used if editing a
> > commit on a local branch) and subsequently git format-patch, which takes
> > a commit from a git repository and turns it into a .patch file: neither
> > of these "converts" r-b's (and other tags) to cc, that's happening in
> > git send-email (see `--suppress-cc` documentation in `man
> > git-send-email`).
> >
>
> Yes, ofcourse git send-email was used to send the patch, not any other
> mail client.
>
> Yes i am also aware that send-email converts rb to CC.
>
> But if you keep working on the local branch, then you would have to
> manually add the r-bs. If you use am of the prev version and develop on
> that, it will automatically add the r-bs.

It looks like there is some misunderstanding here. I think Marijn
doesn't question his R-B (which was present), but tries to point out
that Kuogee might want to adjust his git-send-email invocation. By
default (and that's a good practice, which we should follow),
git-send-email will CC people mentioned in such tags. Marijn didn't
get this email. So, it seems, for some reason this Cc: _mail_ header
was suppressed. Probably git-send-email invocation should be changed
to prevent suppression of adding mentioned people to CC lists.

>
>
> > I can recommend b4: it has lots of useful features including
> > automatically picking up reviews and processing revisions.  It even
> > requires a changelog to be edited ;).  However, finding the right flags
> > and trusting it'll "do as ordered" is a bit daunting at first.
> >
> >>>> ---
> >>>>    drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c | 8 ++++----
> >>>>    1 file changed, 4 insertions(+), 4 deletions(-)
> >>>>
> >>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
> >>>> index bbdc95c..1651cd7 100644
> >>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
> >>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_ctl.c
> >>>> @@ -541,10 +541,10 @@ static void dpu_hw_ctl_intf_cfg_v1(struct dpu_hw_ctl *ctx,
> >>>>            if (cfg->merge_3d)
> >>>>                    DPU_REG_WRITE(c, CTL_MERGE_3D_ACTIVE,
> >>>>                                  BIT(cfg->merge_3d - MERGE_3D_0));
> >>>> -  if (cfg->dsc) {
> >>>> -          DPU_REG_WRITE(&ctx->hw, CTL_FLUSH, DSC_IDX);
> >>>> -          DPU_REG_WRITE(c, CTL_DSC_ACTIVE, cfg->dsc);
> >>>> -  }
> >>>> +
> >>>> +  /* FIXME: fix reset_intf_cfg to handle teardown of dsc */
> >>>
> >>> There's more wrong than just moving (not "fix"ing) this bit of code into
> >>> reset_intf_cfg.  And this will have to be re-wrapped in `if (cfg->dsc)`
> >>> again by reverting this patch.  Perhaps that can be explained, or link
> >>> to Abhinav's explanation to make it clear to readers what this FIXME
> >>> actually means?  Let's wait for Abhinav and Dmitry to confirm the
> >>> desired communication here.
> >>>
> >>> https://lore.kernel.org/linux-arm-msm/ec045d6b-4ffd-0f8c-4011-8db45edc6978@quicinc.com/
> >>>
> >>
> >> Yes, I am fine with linking this explanation in the commit text and
> >> mentioning that till thats fixed, we need to go with this solution. The
> >> FIXME itself is fine, I will work on it and I remember this context well.
> >
> > Looks like it was removed entirely in v3, in favour of only describing
> > it in the patch body.  The wording seems a bit off but that's fine by me
> > if you're picking this up soon anyway.
> >
> > - Marijn



-- 
With best wishes
Dmitry