Re: [Freedreno] [v4] drm/msm/disp/dpu1: turn off vblank irqs aggressively in dpu driver

kalyan_t
2021-02-23T15:13:59Z

On 2021-02-22 21:38, Rob Clark wrote:
> On Thu, Feb 18, 2021 at 4:36 AM Kalyan Thota <kalyan_t@codeaurora.org>
> wrote:
>>
>> Set the flag vblank_disable_immediate = true to turn off vblank irqs
>> immediately as soon as drm_vblank_put is requested so that there are
>> no irqs triggered during idle state. This will reduce cpu wakeups
>> and help in power saving.
>>
>> To enable vblank_disable_immediate flag the underlying KMS driver
>> needs to support high precision vblank timestamping and also a
>> reliable way of providing vblank counter which is incrementing
>> at the leading edge of vblank.
>>
>> This patch also brings in changes to support vblank_disable_immediate
>> requirement in dpu driver.
>>
>> Changes in v1:
>> - Specify reason to add vblank timestamp support. (Rob).
>> - Add changes to provide vblank counter from dpu driver.
>>
>> Changes in v2:
>> - Fix warn stack reported by Rob Clark with v2 patch.
>>
>> Changes in v3:
>> - Move back to HW frame counter (Rob).
>>
>
> could you let me know what the delta was in v4? (No need to resend
> yet, if needed I can amend the commit msg when applying)
>
- Frame count mismatch was causing a DRM WARN stack spew.
DPU HW will increment the frame count at the end of
the sync, where as vblank will be triggered at the
fetch_start counter which is calculated as v_total - vfp.
This is to start fetching early for panels with low
vbp w.r.t hw latency lines.

Add logic to detect the line count if it falls between
vactive and v_total then return incremented frame count value.
> BR,
> -R
>
>> Signed-off-by: Kalyan Thota <kalyan_t@codeaurora.org>
>> ---
>> drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 80
>> ++++++++++++++++++++++
>> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 30 ++++++++
>> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h | 11 +++
>> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h | 1 +
>> .../gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c | 26 +++++++
>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c | 1 +
>> drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h | 1 +
>> drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 5 ++
>> 8 files changed, 155 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> index d4662e8..9a80981 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
>> @@ -65,6 +65,83 @@ static void dpu_crtc_destroy(struct drm_crtc *crtc)
>> kfree(dpu_crtc);
>> }
>>
>> +static struct drm_encoder *get_encoder_from_crtc(struct drm_crtc
>> *crtc)
>> +{
>> + struct drm_device *dev = crtc->dev;
>> + struct drm_encoder *encoder;
>> +
>> + drm_for_each_encoder(encoder, dev)
>> + if (encoder->crtc == crtc)
>> + return encoder;
>> +
>> + return NULL;
>> +}
>> +
>> +static u32 dpu_crtc_get_vblank_counter(struct drm_crtc *crtc)
>> +{
>> + struct drm_encoder *encoder;
>> +
>> + encoder = get_encoder_from_crtc(crtc);
>> + if (!encoder) {
>> + DRM_ERROR("no encoder found for crtc %d\n",
>> crtc->index);
>> + return false;
>> + }
>> +
>> + return dpu_encoder_get_frame_count(encoder);
>> +}
>> +
>> +static bool dpu_crtc_get_scanout_position(struct drm_crtc *crtc,
>> + bool in_vblank_irq,
>> + int *vpos, int *hpos,
>> + ktime_t *stime, ktime_t
>> *etime,
>> + const struct
>> drm_display_mode *mode)
>> +{
>> + unsigned int pipe = crtc->index;
>> + struct drm_encoder *encoder;
>> + int line, vsw, vbp, vactive_start, vactive_end, vfp_end;
>> +
>> + encoder = get_encoder_from_crtc(crtc);
>> + if (!encoder) {
>> + DRM_ERROR("no encoder found for crtc %d\n", pipe);
>> + return false;
>> + }
>> +
>> + vsw = mode->crtc_vsync_end - mode->crtc_vsync_start;
>> + vbp = mode->crtc_vtotal - mode->crtc_vsync_end;
>> +
>> + /*
>> + * the line counter is 1 at the start of the VSYNC pulse and
>> VTOTAL at
>> + * the end of VFP. Translate the porch values relative to the
>> line
>> + * counter positions.
>> + */
>> +
>> + vactive_start = vsw + vbp + 1;
>> + vactive_end = vactive_start + mode->crtc_vdisplay;
>> +
>> + /* last scan line before VSYNC */
>> + vfp_end = mode->crtc_vtotal;
>> +
>> + if (stime)
>> + *stime = ktime_get();
>> +
>> + line = dpu_encoder_get_linecount(encoder);
>> +
>> + if (line < vactive_start)
>> + line -= vactive_start;
>> + else if (line > vactive_end)
>> + line = line - vfp_end - vactive_start;
>> + else
>> + line -= vactive_start;
>> +
>> + *vpos = line;
>> + *hpos = 0;
>> +
>> + if (etime)
>> + *etime = ktime_get();
>> +
>> + return true;
>> +}
>> +
>> static void _dpu_crtc_setup_blend_cfg(struct dpu_crtc_mixer *mixer,
>> struct dpu_plane_state *pstate, struct dpu_format
>> *format)
>> {
>> @@ -1243,6 +1320,8 @@ static const struct drm_crtc_funcs
>> dpu_crtc_funcs = {
>> .early_unregister = dpu_crtc_early_unregister,
>> .enable_vblank = msm_crtc_enable_vblank,
>> .disable_vblank = msm_crtc_disable_vblank,
>> + .get_vblank_timestamp =
>> drm_crtc_vblank_helper_get_vblank_timestamp,
>> + .get_vblank_counter = dpu_crtc_get_vblank_counter,
>> };
>>
>> static const struct drm_crtc_helper_funcs dpu_crtc_helper_funcs = {
>> @@ -1251,6 +1330,7 @@ static const struct drm_crtc_helper_funcs
>> dpu_crtc_helper_funcs = {
>> .atomic_check = dpu_crtc_atomic_check,
>> .atomic_begin = dpu_crtc_atomic_begin,
>> .atomic_flush = dpu_crtc_atomic_flush,
>> + .get_scanout_position = dpu_crtc_get_scanout_position,
>> };
>>
>> /* initialize crtc */
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> index f7f5c25..5cd3f31 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
>> @@ -425,6 +425,36 @@ int dpu_encoder_helper_unregister_irq(struct
>> dpu_encoder_phys *phys_enc,
>> return 0;
>> }
>>
>> +int dpu_encoder_get_frame_count(struct drm_encoder *drm_enc)
>> +{
>> + struct dpu_encoder_virt *dpu_enc;
>> + struct dpu_encoder_phys *phys;
>> + int framecount = 0;
>> +
>> + dpu_enc = to_dpu_encoder_virt(drm_enc);
>> + phys = dpu_enc ? dpu_enc->cur_master : NULL;
>> +
>> + if (phys && phys->ops.get_frame_count)
>> + framecount = phys->ops.get_frame_count(phys);
>> +
>> + return framecount;
>> +}
>> +
>> +int dpu_encoder_get_linecount(struct drm_encoder *drm_enc)
>> +{
>> + struct dpu_encoder_virt *dpu_enc;
>> + struct dpu_encoder_phys *phys;
>> + int linecount = 0;
>> +
>> + dpu_enc = to_dpu_encoder_virt(drm_enc);
>> + phys = dpu_enc ? dpu_enc->cur_master : NULL;
>> +
>> + if (phys && phys->ops.get_line_count)
>> + linecount = phys->ops.get_line_count(phys);
>> +
>> + return linecount;
>> +}
>> +
>> void dpu_encoder_get_hw_resources(struct drm_encoder *drm_enc,
>> struct dpu_encoder_hw_resources
>> *hw_res)
>> {
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
>> index b491346..99a5d73 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
>> @@ -156,5 +156,16 @@ void dpu_encoder_prepare_commit(struct
>> drm_encoder *drm_enc);
>> */
>> void dpu_encoder_set_idle_timeout(struct drm_encoder *drm_enc,
>> u32
>> idle_timeout);
>> +/**
>> + * dpu_encoder_get_linecount - get interface line count for the
>> encoder.
>> + * @drm_enc: Pointer to previously created drm encoder structure
>> + */
>> +int dpu_encoder_get_linecount(struct drm_encoder *drm_enc);
>> +
>> +/**
>> + * dpu_encoder_get_frame_count - get interface frame count for the
>> encoder.
>> + * @drm_enc: Pointer to previously created drm encoder structure
>> + */
>> +int dpu_encoder_get_frame_count(struct drm_encoder *drm_enc);
>>
>> #endif /* __DPU_ENCODER_H__ */
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
>> index f8f2515..ecbc4be 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys.h
>> @@ -143,6 +143,7 @@ struct dpu_encoder_phys_ops {
>> void (*prepare_idle_pc)(struct dpu_encoder_phys *phys_enc);
>> void (*restore)(struct dpu_encoder_phys *phys);
>> int (*get_line_count)(struct dpu_encoder_phys *phys);
>> + int (*get_frame_count)(struct dpu_encoder_phys *phys);
>> };
>>
>> /**
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
>> index 9a69fad..0e06b7e 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
>> @@ -658,6 +658,31 @@ static int dpu_encoder_phys_vid_get_line_count(
>> return
>> phys_enc->hw_intf->ops.get_line_count(phys_enc->hw_intf);
>> }
>>
>> +static int dpu_encoder_phys_vid_get_frame_count(
>> + struct dpu_encoder_phys *phys_enc)
>> +{
>> + struct intf_status s = {0};
>> + u32 fetch_start = 0;
>> + struct drm_display_mode mode = phys_enc->cached_mode;
>> +
>> + if (!dpu_encoder_phys_vid_is_master(phys_enc))
>> + return -EINVAL;
>> +
>> + if (!phys_enc->hw_intf || !phys_enc->hw_intf->ops.get_status)
>> + return -EINVAL;
>> +
>> + phys_enc->hw_intf->ops.get_status(phys_enc->hw_intf, &s);
>> +
>> + if (s.is_prog_fetch_en && s.is_en) {
>> + fetch_start = mode.vtotal - (mode.vsync_start -
>> mode.vdisplay);
>> + if ((s.line_count > fetch_start) &&
>> + (s.line_count <= mode.vtotal))
>> + return s.frame_count + 1;
>> + }
>> +
>> + return s.frame_count;
>> +}
>> +
>> static void dpu_encoder_phys_vid_init_ops(struct dpu_encoder_phys_ops
>> *ops)
>> {
>> ops->is_master = dpu_encoder_phys_vid_is_master;
>> @@ -676,6 +701,7 @@ static void dpu_encoder_phys_vid_init_ops(struct
>> dpu_encoder_phys_ops *ops)
>> ops->handle_post_kickoff =
>> dpu_encoder_phys_vid_handle_post_kickoff;
>> ops->needs_single_flush =
>> dpu_encoder_phys_vid_needs_single_flush;
>> ops->get_line_count = dpu_encoder_phys_vid_get_line_count;
>> + ops->get_frame_count = dpu_encoder_phys_vid_get_frame_count;
>> }
>>
>> struct dpu_encoder_phys *dpu_encoder_phys_vid_init(
>> 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 6f0f545..717178b 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c
>> @@ -256,6 +256,7 @@ static void dpu_hw_intf_get_status(
>> struct dpu_hw_blk_reg_map *c = &intf->hw;
>>
>> s->is_en = DPU_REG_READ(c, INTF_TIMING_ENGINE_EN);
>> + s->is_prog_fetch_en = !!(DPU_REG_READ(c, INTF_CONFIG) &
>> BIT(31));
>> if (s->is_en) {
>> s->frame_count = DPU_REG_READ(c, INTF_FRAME_COUNT);
>> s->line_count = DPU_REG_READ(c, INTF_LINE_COUNT);
>> 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 0ead64d..3568be8 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h
>> @@ -40,6 +40,7 @@ struct intf_prog_fetch {
>>
>> struct intf_status {
>> u8 is_en; /* interface timing engine is enabled
>> or not */
>> + u8 is_prog_fetch_en; /* interface prog fetch counter is
>> enabled or not */
>> u32 frame_count; /* frame count since timing engine
>> enabled */
>> u32 line_count; /* current line count including
>> blanking */
>> };
>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>> index 374b0e8..ed636f1 100644
>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
>> @@ -14,6 +14,7 @@
>>
>> #include <drm/drm_crtc.h>
>> #include <drm/drm_file.h>
>> +#include <drm/drm_vblank.h>
>>
>> #include "msm_drv.h"
>> #include "msm_mmu.h"
>> @@ -1020,6 +1021,10 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
>> */
>> dev->mode_config.allow_fb_modifiers = true;
>>
>> + dev->max_vblank_count = 0xffffffff;
>> + /* Disable vblank irqs aggressively for power-saving */
>> + dev->vblank_disable_immediate = true;
>> +
>> /*
>> * _dpu_kms_drm_obj_init should create the DRM related objects
>> * i.e. CRTCs, planes, encoders, connectors and so forth
>> --
>> 2.7.4
>>
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