Message-ID: <CAA8EJpoOZOwLfa4tx1zhp8w5cY+3OR4J4o0xjTaNO5SMM=F6Bg@mail.gmail.com>
Date:   Sat, 15 Apr 2023 01:53:58 +0300
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Abhinav Kumar <quic_abhinavk@...cinc.com>
Cc:     Marijn Suijten <marijn.suijten@...ainline.org>,
        Kuogee Hsieh <quic_khsieh@...cinc.com>, robdclark@...il.com,
        sean@...rly.run, swboyd@...omium.org, dianders@...omium.org,
        vkoul@...nel.org, daniel@...ll.ch, airlied@...il.com,
        agross@...nel.org, andersson@...nel.org, quic_sbillaka@...cinc.com,
        freedreno@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-arm-msm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] drm/msm/dpu: always program dsc active bits

On Sat, 15 Apr 2023 at 00:03, Abhinav Kumar <quic_abhinavk@...cinc.com> wrote:
>
>
>
> On 4/14/2023 1:58 PM, Dmitry Baryshkov wrote:
> > On Fri, 14 Apr 2023 at 21:55, Abhinav Kumar <quic_abhinavk@...cinc.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@...cinc.com>
> >>>>>> Reviewed-by: Marijn Suijten <marijn.suijten@...ainline.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.
> >
>
> Yeah I understood that part. There were two issues here:
>
> 1) My r-b got dropped and that was because am wasn't used to
> automatically retain tags from prev version.
>
> If you dont add the r-bs either manually or by am, then folks wont be
> part of CC either

Just as a note: there is nothing wrong with adding tags manually. I do
that for some of my patchsets (and sometimes I miss them too).

>
> 2) I synced with kuogee. his git version seems to be quite old which is
> not adding the folks from r-b to cc. So there was nothing wrong with
> invocation, just versioning.

Ack. Thanks for updating it.

>
>
> >>
> >>
> >>> 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

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