RE: [PATCH 4/4] drm/msm/disp/dpu1: add color management support for the crtc

[Kalyan Thota]

>-----Original Message-----
>From: Kalyan Thota <kalyant@xxxxxxxxxxxxxxxx>
>Sent: Wednesday, November 9, 2022 6:53 PM
>To: dmitry.baryshkov@xxxxxxxxxx; Kalyan Thota (QUIC)
><quic_kalyant@xxxxxxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; linux-arm-
>msm@xxxxxxxxxxxxxxx; freedreno@xxxxxxxxxxxxxxxxxxxxx;
>devicetree@xxxxxxxxxxxxxxx
>Cc: linux-kernel@xxxxxxxxxxxxxxx; robdclark@xxxxxxxxxxxx;
>dianders@xxxxxxxxxxxx; swboyd@xxxxxxxxxxxx; Vinod Polimera (QUIC)
><quic_vpolimer@xxxxxxxxxxx>; Abhinav Kumar (QUIC)
><quic_abhinavk@xxxxxxxxxxx>
>Subject: RE: [PATCH 4/4] drm/msm/disp/dpu1: add color management support
>for the crtc
>
>
>
>>-----Original Message-----
>>From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
>>Sent: Wednesday, November 9, 2022 6:02 PM
>>To: Kalyan Thota (QUIC) <quic_kalyant@xxxxxxxxxxx>; dri-
>>devel@xxxxxxxxxxxxxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx;
>>freedreno@xxxxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx
>>Cc: linux-kernel@xxxxxxxxxxxxxxx; robdclark@xxxxxxxxxxxx;
>>dianders@xxxxxxxxxxxx; swboyd@xxxxxxxxxxxx; Vinod Polimera (QUIC)
>><quic_vpolimer@xxxxxxxxxxx>; Abhinav Kumar (QUIC)
>><quic_abhinavk@xxxxxxxxxxx>
>>Subject: Re: [PATCH 4/4] drm/msm/disp/dpu1: add color management
>>support for the crtc
>>
>>WARNING: This email originated from outside of Qualcomm. Please be wary
>>of any links or attachments, and do not enable macros.
>>
>>On 09/11/2022 15:16, Kalyan Thota wrote:
>>> Add color management support for the crtc provided there are enough
>>> dspps that can be allocated from the catalogue
>>>
>>> Signed-off-by: Kalyan Thota <quic_kalyant@xxxxxxxxxxx>
>>> ---
>>>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    | 15 ++++++--
>>>   drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h    |  6 ++++
>>>   drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 11 +++---
>>>   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     | 53
>>+++++++++++++++++++++++++++++
>>>   4 files changed, 77 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>>> index 4170fbe..6bd3a64 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>>> @@ -18,9 +18,11 @@
>>>   #include <drm/drm_flip_work.h>
>>>   #include <drm/drm_framebuffer.h>
>>>   #include <drm/drm_mode.h>
>>> +#include <drm/drm_mode_object.h>
>>>   #include <drm/drm_probe_helper.h>
>>>   #include <drm/drm_rect.h>
>>>   #include <drm/drm_vblank.h>
>>> +#include "../../../drm_crtc_internal.h"
>>
>>If it's internal, it is not supposed to be used by other parties,
>>including the msm drm. At least a comment why you are including this file would
>be helpful.
>>
>>>
>>>   #include "dpu_kms.h"
>>>   #include "dpu_hw_lm.h"
>>> @@ -553,6 +555,17 @@ static void _dpu_crtc_complete_flip(struct
>>> drm_crtc
>>*crtc)
>>>       spin_unlock_irqrestore(&dev->event_lock, flags);
>>>   }
>>>
>>> +bool dpu_crtc_has_color_enabled(struct drm_crtc *crtc) {
>>> +     u32 ctm_id = crtc->dev->mode_config.ctm_property->base.id;
>>> +     u32 gamma_id = crtc->dev->mode_config.gamma_lut_property->base.id;
>>> +     u32 degamma_id =
>>> +crtc->dev->mode_config.degamma_lut_property->base.id;
>>> +
>>> +     return !!(drm_mode_obj_find_prop_id(&crtc->base, ctm_id) ||
>>> +                drm_mode_obj_find_prop_id(&crtc->base, gamma_id) ||
>>> +                drm_mode_obj_find_prop_id(&crtc->base, degamma_id));
>>> +}
>>> +
>>>   enum dpu_intf_mode dpu_crtc_get_intf_mode(struct drm_crtc *crtc)
>>>   {
>>>       struct drm_encoder *encoder;
>>> @@ -1604,8 +1617,6 @@ struct drm_crtc *dpu_crtc_init(struct
>>> drm_device *dev, struct drm_plane *plane,
>>>
>>>       drm_crtc_helper_add(crtc, &dpu_crtc_helper_funcs);
>>>
>>> -     drm_crtc_enable_color_mgmt(crtc, 0, true, 0);
>>> -
>>>       /* save user friendly CRTC name for later */
>>>       snprintf(dpu_crtc->name, DPU_CRTC_NAME_SIZE, "crtc%u",
>>> crtc->base.id);
>>>
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
>>> index 539b68b..8bac395 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
>>> @@ -300,4 +300,10 @@ static inline enum dpu_crtc_client_type
>>dpu_crtc_get_client_type(
>>>       return crtc && crtc->state ? RT_CLIENT : NRT_CLIENT;
>>>   }
>>>
>>> +/**
>>> + * dpu_crtc_has_color_enabled - check if the crtc has color
>>> +management enabled
>>> + * @crtc: Pointer to drm crtc object  */ bool
>>> +dpu_crtc_has_color_enabled(struct drm_crtc *crtc);
>>> +
>>>   #endif /* _DPU_CRTC_H_ */
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> index 4c56a16..ebc3f25 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>>> @@ -545,7 +545,8 @@ bool dpu_encoder_use_dsc_merge(struct
>drm_encoder
>>*drm_enc)
>>>   static struct msm_display_topology dpu_encoder_get_topology(
>>>                       struct dpu_encoder_virt *dpu_enc,
>>>                       struct dpu_kms *dpu_kms,
>>> -                     struct drm_display_mode *mode)
>>> +                     struct drm_display_mode *mode,
>>> +                     struct drm_crtc *crtc)
>>>   {
>>>       struct msm_display_topology topology = {0};
>>>       int i, intf_count = 0;
>>> @@ -573,11 +574,9 @@ static struct msm_display_topology
>>dpu_encoder_get_topology(
>>>       else
>>>               topology.num_lm = (mode->hdisplay > MAX_HDISPLAY_SPLIT)
>>> ? 2 : 1;
>>>
>>> -     if (dpu_enc->disp_info.intf_type == DRM_MODE_ENCODER_DSI) {
>>> -             if (dpu_kms->catalog->dspp &&
>>> -                     (dpu_kms->catalog->dspp_count >= topology.num_lm))
>>> +     if (dpu_crtc_has_color_enabled(crtc) &&
>>> +             (dpu_kms->catalog->dspp_count >= topology.num_lm))
>>
>>See the comment to the previous patch. It still applies here.
>>
>>>                       topology.num_dspp = topology.num_lm;
>>> -     }
>>>
>>>       topology.num_enc = 0;
>>>       topology.num_intf = intf_count; @@ -643,7 +642,7 @@ static int
>>> dpu_encoder_virt_atomic_check(
>>>               }
>>>       }
>>>
>>> -     topology = dpu_encoder_get_topology(dpu_enc, dpu_kms, adj_mode);
>>> +     topology = dpu_encoder_get_topology(dpu_enc, dpu_kms, adj_mode,
>>> + crtc_state->crtc);
>>>
>>>       /* Reserve dynamic resources now. */
>>>       if (!ret) {
>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>> index 552a89c..47a73fa 100644
>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>>> @@ -13,6 +13,7 @@
>>>   #include <linux/dma-buf.h>
>>>   #include <linux/of_irq.h>
>>>   #include <linux/pm_opp.h>
>>> +#include <linux/bitops.h>
>>>
>>>   #include <drm/drm_crtc.h>
>>>   #include <drm/drm_file.h>
>>> @@ -537,6 +538,44 @@ static void dpu_kms_wait_flush(struct msm_kms
>>*kms, unsigned crtc_mask)
>>>               dpu_kms_wait_for_commit_done(kms, crtc);
>>>   }
>>>
>>> +/**
>>> + * _dpu_kms_possible_dspps - Evaluate how many dspps pairs can be
>>facilitated
>>> +                             to enable color features for crtcs.
>>> + * @dpu_kms:    Pointer to dpu kms structure
>>> + * Returns:     count of dspp pairs
>>> + *
>>> + * Baring single entry, if atleast 2 dspps are available in the
>>> +catalogue,
>>> + * then color can be enabled for that crtc  */ static inline u32
>>> +_dpu_kms_possible_dspps(struct dpu_kms *dpu_kms) {
>>> +
>>> +     u32 num_dspps = dpu_kms->catalog->dspp_count;
>>> +
>>> +     if (num_dspps > 1)
>>> +             num_dspps =
>>> +                     !(num_dspps % 2) ? num_dspps / 2 : (num_dspps -
>>> + 1) / 2;
>>
>>Ugh. No. Please spell this clearly rather than using nice math and
>>ternary
>>operators:
>>
>>if (num_dspps <= 1)
>>   return num_dspps;
>>else
>>   return num_dspps / 2;
>>
>>You see, if num_dspps %2 ! =0, then num_dspps / 2 == (num_dspps_2 - 1) / 2.
>>
>>
>>> +
>>> +     return num_dspps;
>>> +}
>>> +
>>> +static u32 _dpu_kms_attach_color(struct drm_device *dev, u32 enc_mask,
>>> +                                             u32 num_dspps) {
>>> +     struct drm_encoder *encoder;
>>> +     struct drm_crtc *crtc;
>>> +
>>> +     drm_for_each_encoder_mask(encoder, dev, enc_mask) {
>>> +             crtc = drm_crtc_from_index(dev, ffs(encoder->possible_crtcs) - 1);
>>> +             if (num_dspps && crtc) {
>>> +                     drm_crtc_enable_color_mgmt(crtc, 0, true, 0);
>>> +                     num_dspps--;
>>
>>Please.  You can do this at the time you create the crtc. It would be much
>simpler.
>>
>Following are the cases that I have considered.
>1) DP can be first among the encoder list
>2) we can have more than 1 primary display.
>
>Since encoder list operation is iterative, we cannot go back and set the color, if
>we end up having unused dspp's Secondly, it will be a bit complex logic to save
>the dspps for primary assuming DSI/eDP will be later in the list, and comeback to
>assign to DP as well if there are enough dspps (run through the loop twice)
>
>I have used 2 encoder masks for primary and external. And i have preferred all the
>primary displays to get a first allocation and then move to external.
>
>Let me know if your thoughts.
>
On second thought, with the addition of connector_type, logic can be simplified, let me add those changes
>
>>> +             }
>>> +     }
>>> +
>>> +     return num_dspps;
>>> +}
>>> +
>>>   static int _dpu_kms_initialize_dsi(struct drm_device *dev,
>>>                                   struct msm_drm_private *priv,
>>>                                   struct dpu_kms *dpu_kms) @@ -747,6
>>> +786,8 @@ static int _dpu_kms_drm_obj_init(struct dpu_kms *dpu_kms)
>>>
>>>       int primary_planes_idx = 0, cursor_planes_idx = 0, i, ret;
>>>       int max_crtc_count;
>>> +     u32 num_dspps, primary_enc_mask = 0, external_enc_mask = 0;
>>> +
>>>       dev = dpu_kms->dev;
>>>       priv = dev->dev_private;
>>>       catalog = dpu_kms->catalog;
>>> @@ -796,6 +837,7 @@ static int _dpu_kms_drm_obj_init(struct dpu_kms
>>*dpu_kms)
>>>       }
>>>
>>>       max_crtc_count = min(max_crtc_count, primary_planes_idx);
>>> +     num_dspps = _dpu_kms_possible_dspps(dpu_kms);
>>>
>>>       /* Create one CRTC per encoder */
>>>       encoder = list_first_entry(&(dev)->mode_config.encoder_list,
>>> @@ -808,9 +850,20 @@ static int _dpu_kms_drm_obj_init(struct dpu_kms
>>*dpu_kms)
>>>               }
>>>               priv->crtcs[priv->num_crtcs++] = crtc;
>>>               encoder->possible_crtcs = 1 << drm_crtc_index(crtc);
>>> +
>>> +             if (!dpu_encoder_is_external(encoder) &&
>>> +                     !dpu_encoder_is_virtual(encoder))
>>
>>if (dpu_encoder_internal_output(encoder))
>>
>>> +                     primary_enc_mask |= drm_encoder_mask(encoder);
>>> +             else if (dpu_encoder_is_external(encoder))
>>> +                     external_enc_mask |= drm_encoder_mask(encoder);
>>> +
>>>               encoder = list_next_entry(encoder, head);
>>>       }
>>>
>>> +     /* Prefer Primary encoders in registering for color support */
>>> +     num_dspps = _dpu_kms_attach_color(dev, primary_enc_mask,
>>num_dspps);
>>> +     num_dspps = _dpu_kms_attach_color(dev, external_enc_mask,
>>> + num_dspps);
>>> +
>>>       return 0;
>>>   }
>>>
>>
>>--
>>With best wishes
>>Dmitry
>