Re: [PATCH] drm/msm/dpu: Fix encoder CRC to account for CTM enablement

From: Rob Clark
Date: Tue Nov 21 2023 - 19:27:51 EST

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In reply to: Abhinav Kumar: "Re: [PATCH] drm/msm/dpu: Fix encoder CRC to account for CTM enablement"
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On Tue, Nov 21, 2023 at 4:41 PM Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
>
>
>
> On 10/24/2023 12:01 PM, Abhinav Kumar wrote:
> >
> >
> > On 10/23/2023 4:03 PM, Dmitry Baryshkov wrote:
> >> On Tue, 24 Oct 2023 at 01:36, Rob Clark <robdclark@xxxxxxxxx> wrote:
> >>>
> >>> On Mon, Oct 23, 2023 at 3:30 PM Dmitry Baryshkov
> >>> <dmitry.baryshkov@xxxxxxxxxx> wrote:
> >>>>
> >>>> On Tue, 24 Oct 2023 at 01:12, Rob Clark <robdclark@xxxxxxxxx> wrote:
> >>>>>
> >>>>> From: Rob Clark <robdclark@xxxxxxxxxxxx>
> >>>>>
> >>>>> Seems like we need to pick INPUT_SEL=1 when CTM is enabled. But not
> >>>>> otherwise.
> >>>>>
> >>>>> Suggested-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> >>>>> Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
> >>>>> ---
> >
> > I cannot find anything in the docs which suggest this solution is correct.
> >
> > Different blocks in the DPU pipeline have their own CRC (MISR) registers
> > like LM, intf etc.
> >
> > We dont need to change INPUT_SEL to tell DPU from which pipeline to take
> > the CRC from as each of them have their own registers.
> >
> > INPUT_SEL is controlling whether the CRC needs to be calculated over the
> > entire display timings or only the active pixels. I am unable to tell at
> > the moment why this is making a difference in this use-case.
> >
> > Since I am unable to find any documentation proving this solution is
> > correct so far, unfortunately I would hold this back till then.
> >
> > We will investigate this issue and report our findings on this thread on
> > how to proceed.
> >
>
> Alright, we debugged and also found some more answers.
>
> The correct solution is indeed to set INPUT_SEL = 1 but let me explain
> why and what should be the correct way.
>
> INPUT_SEL was indeed telling whether to compute CRC over active pixels
> or active pixels + timings like I wrote before but this behavior changed
> since some chipsets.
>
> Now, INPUT_SEL = 0 means compute CRC *only* over timings and not the
> active area (and not display + timings like before) and like mentioned
> before this has nothing to do with what is the input to the CRC. Not
> covering the active area will not change the CRC at all as Rob reported
> but its not specific to CTM.
>
> Which means we should have been setting INPUT_SEL=1 whenever we use INTF
> CRC irrespective of whether CTM is used or not.
>
> What this also means is INTF CRC was not working correctly at all so far
> irrespecive of CTM or not because it was always computing CRC only on
> the timings (non-active area).
>
> This was not caught so far because it looks like IGT's
> kms_pipe_crc_basic test which was used to validate this only compares
> CRC between two frames of the same content to match if they were equal
> and not changing contents and comparing like kms_plane does. It will
> pass as CRC would not have changed.
>
> Now coming to the fix, the reset value of this register INTF_MISR_CTRL
> already sets the INPUT_SEL bit (or unsets it) correctly based on
> whichever DPU version is used so we should just change the
> dpu_hw_setup_misr() to a read on the register followed by ORing the
> required bits without touching INPUT_SEL and write.
>
> That will address this issue and also cover version control since the
> expected value of this bit has changed across DPU revisions.

Ok, thanks for following up on this. Mind posting a patch to
supersede this one?

BR,
-R

> >>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 2 +-
> >>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 4 ++--
> >>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h | 3 ++-
> >>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c | 4 ++--
> >>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h | 2 +-
> >>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_lm.c | 2 +-
> >>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.c | 5 ++++-
> >>>>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.h | 3 ++-
> >>>>> 8 files changed, 15 insertions(+), 10 deletions(-)
> >>>>>
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> >>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> >>>>> index 2b83a13b3aa9..d93a92ffd5df 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> >>>>> @@ -134,7 +134,7 @@ static void dpu_crtc_setup_encoder_misr(struct
> >>>>> drm_crtc *crtc)
> >>>>> struct drm_encoder *drm_enc;
> >>>>>
> >>>>> drm_for_each_encoder_mask(drm_enc, crtc->dev,
> >>>>> crtc->state->encoder_mask)
> >>>>> - dpu_encoder_setup_misr(drm_enc);
> >>>>> + dpu_encoder_setup_misr(drm_enc, !!crtc->state->ctm);
> >>>>> }
> >>>>>
> >>>>> static int dpu_crtc_set_crc_source(struct drm_crtc *crtc, const
> >>>>> char *src_name)
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>>>> index b0a7908418ed..12ee7acb5ea6 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>>>> @@ -241,7 +241,7 @@ int dpu_encoder_get_crc_values_cnt(const struct
> >>>>> drm_encoder *drm_enc)
> >>>>> return num_intf;
> >>>>> }
> >>>>>
> >>>>> -void dpu_encoder_setup_misr(const struct drm_encoder *drm_enc)
> >>>>> +void dpu_encoder_setup_misr(const struct drm_encoder *drm_enc,
> >>>>> bool has_ctm)
> >>>>> {
> >>>>> struct dpu_encoder_virt *dpu_enc;
> >>>>>
> >>>>> @@ -255,7 +255,7 @@ void dpu_encoder_setup_misr(const struct
> >>>>> drm_encoder *drm_enc)
> >>>>> if (!phys->hw_intf || !phys->hw_intf->ops.setup_misr)
> >>>>> continue;
> >>>>>
> >>>>> - phys->hw_intf->ops.setup_misr(phys->hw_intf, true, 1);
> >>>>> + phys->hw_intf->ops.setup_misr(phys->hw_intf, true,
> >>>>> 1, has_ctm);
> >>>>> }
> >>>>> }
> >>>>>
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> >>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> >>>>> index 4c05fd5e9ed1..510783b2fb24 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> >>>>> @@ -169,8 +169,9 @@ int dpu_encoder_get_crc_values_cnt(const struct
> >>>>> drm_encoder *drm_enc);
> >>>>> /**
> >>>>> * dpu_encoder_setup_misr - enable misr calculations
> >>>>> * @drm_enc: Pointer to previously created drm encoder structure
> >>>>> + * @has_ctm: Is CTM enabled
> >>>>> */
> >>>>> -void dpu_encoder_setup_misr(const struct drm_encoder *drm_encoder);
> >>>>> +void dpu_encoder_setup_misr(const struct drm_encoder *drm_encoder,
> >>>>> bool has_ctm);
> >>>>>
> >>>>> /**
> >>>>> * dpu_encoder_get_crc - get the crc value from interface blocks
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> >>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> >>>>> index e8b8908d3e12..cb06f80cc671 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
> >>>>> @@ -318,9 +318,9 @@ static u32 dpu_hw_intf_get_line_count(struct
> >>>>> dpu_hw_intf *intf)
> >>>>> return DPU_REG_READ(c, INTF_LINE_COUNT);
> >>>>> }
> >>>>>
> >>>>> -static void dpu_hw_intf_setup_misr(struct dpu_hw_intf *intf, bool
> >>>>> enable, u32 frame_count)
> >>>>> +static void dpu_hw_intf_setup_misr(struct dpu_hw_intf *intf, bool
> >>>>> enable, u32 frame_count, bool has_ctm)
> >>>>> {
> >>>>> - dpu_hw_setup_misr(&intf->hw, INTF_MISR_CTRL, enable,
> >>>>> frame_count);
> >>>>> + dpu_hw_setup_misr(&intf->hw, INTF_MISR_CTRL, enable,
> >>>>> frame_count, has_ctm);
> >>>>
> >>>> I'm not sure about the dpu_encoder and dpu_hw_intf interfaces. But
> >>>> dpu_hw_setup_misr definitely needs the `u8 input_sel` parameter
> >>>> instead of `bool has_ctm`.
> >>>
> >>> That seems a bit premature without knowing what the other values are.
> >>> (And I also question a bit the whole abstraction layer thing if it is
> >>> taking directly register bitfield enum's..)
> >>
> >> dpu_hw_intf and especially dpu_hw_util are not real abstractions. I
> >> always viewed them as useful low-level helpers.
> >>
> >> I think that has_ctm is valid at the dpu_encoder level, which selects
> >> which input to use. on the lower levels has_ctm doesn't make sense.
> >> IOW dpu_hw_setup_misr can be used to setup MISR for other blocks,
> >> where CTM doesn't exist.
> >>
> >>>
> >>> BR,
> >>> -R
> >>>
> >>>> Most likely, I'd use u8 for dpu_hw_intf operation too.
> >>>>
> >>>> Could you please adjust?
> >>>>
> >>>>> }
> >>>>>
> >>>>> static int dpu_hw_intf_collect_misr(struct dpu_hw_intf *intf, u32
> >>>>> *misr_value)
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
> >>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
> >>>>> index c539025c418b..95aafc4cf58e 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
> >>>>> @@ -95,7 +95,7 @@ struct dpu_hw_intf_ops {
> >>>>>
> >>>>> void (*bind_pingpong_blk)(struct dpu_hw_intf *intf,
> >>>>> const enum dpu_pingpong pp);
> >>>>> - void (*setup_misr)(struct dpu_hw_intf *intf, bool enable,
> >>>>> u32 frame_count);
> >>>>> + void (*setup_misr)(struct dpu_hw_intf *intf, bool enable,
> >>>>> u32 frame_count, bool has_ctm);
> >>>>> int (*collect_misr)(struct dpu_hw_intf *intf, u32
> >>>>> *misr_value);
> >>>>>
> >>>>> // Tearcheck on INTF since DPU 5.0.0
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_lm.c
> >>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_lm.c
> >>>>> index d1c3bd8379ea..2efe29396c6a 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_lm.c
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_lm.c
> >>>>> @@ -83,7 +83,7 @@ static void dpu_hw_lm_setup_border_color(struct
> >>>>> dpu_hw_mixer *ctx,
> >>>>>
> >>>>> static void dpu_hw_lm_setup_misr(struct dpu_hw_mixer *ctx, bool
> >>>>> enable, u32 frame_count)
> >>>>> {
> >>>>> - dpu_hw_setup_misr(&ctx->hw, LM_MISR_CTRL, enable,
> >>>>> frame_count);
> >>>>> + dpu_hw_setup_misr(&ctx->hw, LM_MISR_CTRL, enable,
> >>>>> frame_count, false);
> >>>>> }
> >>>>>
> >>>>> static int dpu_hw_lm_collect_misr(struct dpu_hw_mixer *ctx, u32
> >>>>> *misr_value)
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.c
> >>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.c
> >>>>> index 9d2273fd2fed..528b8439209f 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.c
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.c
> >>>>> @@ -483,7 +483,7 @@ void _dpu_hw_setup_qos_lut(struct
> >>>>> dpu_hw_blk_reg_map *c, u32 offset,
> >>>>>
> >>>>> void dpu_hw_setup_misr(struct dpu_hw_blk_reg_map *c,
> >>>>> u32 misr_ctrl_offset,
> >>>>> - bool enable, u32 frame_count)
> >>>>> + bool enable, u32 frame_count, bool has_ctm)
> >>>>> {
> >>>>> u32 config = 0;
> >>>>>
> >>>>> @@ -496,6 +496,9 @@ void dpu_hw_setup_misr(struct
> >>>>> dpu_hw_blk_reg_map *c,
> >>>>> config = (frame_count & MISR_FRAME_COUNT_MASK) |
> >>>>> MISR_CTRL_ENABLE | MISR_CTRL_FREE_RUN_MASK;
> >>>>>
> >>>>> + if (!has_ctm)
> >>>>> + config |= 1 << 24;
> >>>>
> >>>> Please define MISR_CTRL_INPUT_SEL instead.
> >>>>
> >>>>> +
> >>>>> DPU_REG_WRITE(c, misr_ctrl_offset, config);
> >>>>> } else {
> >>>>> DPU_REG_WRITE(c, misr_ctrl_offset, 0);
> >>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.h
> >>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.h
> >>>>> index 1f6079f47071..e42d9d00e40e 100644
> >>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.h
> >>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_util.h
> >>>>> @@ -360,7 +360,8 @@ void _dpu_hw_setup_qos_lut(struct
> >>>>> dpu_hw_blk_reg_map *c, u32 offset,
> >>>>> void dpu_hw_setup_misr(struct dpu_hw_blk_reg_map *c,
> >>>>> u32 misr_ctrl_offset,
> >>>>> bool enable,
> >>>>> - u32 frame_count);
> >>>>> + u32 frame_count,
> >>>>> + bool has_ctm);
> >>>>>
> >>>>> int dpu_hw_collect_misr(struct dpu_hw_blk_reg_map *c,
> >>>>> u32 misr_ctrl_offset,
> >>>>> --
> >>>>> 2.41.0
> >>>>>
> >>>>
> >>>>
> >>>> --
> >>>> With best wishes
> >>>> Dmitry
> >>
> >>
> >>

Next message: Stephen Rothwell: "linux-next: manual merge of the drm tree with the drm-misc-fixes tree"
Previous message: Hyeonggon Yoo: "Re: [PATCH v5 1/9] slub: Reflow ___slab_alloc()"
In reply to: Abhinav Kumar: "Re: [PATCH] drm/msm/dpu: Fix encoder CRC to account for CTM enablement"
Next in thread: Abhinav Kumar: "Re: [PATCH] drm/msm/dpu: Fix encoder CRC to account for CTM enablement"
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