| Message ID | 20200110092127.27847-4-tzimmermann@suse.de (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | drm: Clean up VBLANK callbacks in struct drm_driver | expand |
On Fri, 10 Jan 2020, Thomas Zimmermann <tzimmermann@suse.de> wrote: > The callback struct drm_driver.get_scanout_position() is deprecated in > favor of struct drm_crtc_helper_funcs.get_scanout_position(). > > i915 doesn't use CRTC helpers. The patch duplicates the caller > drm_calc_vbltimestamp_from_scanoutpos() for i915, such that the callback > function is not needed. > > Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> > --- > drivers/gpu/drm/i915/i915_drv.c | 3 +- > drivers/gpu/drm/i915/i915_irq.c | 117 ++++++++++++++++++++++++++++++-- > drivers/gpu/drm/i915/i915_irq.h | 9 +-- > 3 files changed, 119 insertions(+), 10 deletions(-) Not really enthusiastic about the diffstat in a "cleanup" series. I wonder if you could add a generic helper version of drm_calc_vbltimestamp_from_scanoutpos where you pass the get_scanout_position function as a parameter. Both drm_calc_vbltimestamp_from_scanoutpos and the new i915_calc_vbltimestamp_from_scanoutpos would then be fairly thin wrappers passing in the relevant get_scanout_position function. This would reduce the almost identical duplication of the function in i915. BR, Jani. > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c > index f7385abdd74b..4a0a7fb85c53 100644 > --- a/drivers/gpu/drm/i915/i915_drv.c > +++ b/drivers/gpu/drm/i915/i915_drv.c > @@ -2769,8 +2769,7 @@ static struct drm_driver driver = { > .gem_prime_export = i915_gem_prime_export, > .gem_prime_import = i915_gem_prime_import, > > - .get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos, > - .get_scanout_position = i915_get_crtc_scanoutpos, > + .get_vblank_timestamp = i915_calc_vbltimestamp_from_scanoutpos, > > .dumb_create = i915_gem_dumb_create, > .dumb_map_offset = i915_gem_dumb_mmap_offset, > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c > index afc6aad9bf8c..99d0c3b0feae 100644 > --- a/drivers/gpu/drm/i915/i915_irq.c > +++ b/drivers/gpu/drm/i915/i915_irq.c > @@ -52,6 +52,11 @@ > #include "i915_trace.h" > #include "intel_pm.h" > > +/* Retry timestamp calculation up to 3 times to satisfy > + * drm_timestamp_precision before giving up. > + */ > +#define I915_TIMESTAMP_MAXRETRIES 3 > + > /** > * DOC: interrupt handling > * > @@ -762,10 +767,11 @@ static int __intel_get_crtc_scanline(struct intel_crtc *crtc) > return (position + crtc->scanline_offset) % vtotal; > } > > -bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int index, > - bool in_vblank_irq, int *vpos, int *hpos, > - ktime_t *stime, ktime_t *etime, > - const struct drm_display_mode *mode) > +static bool i915_get_crtc_scanoutpos(struct drm_device *dev, > + unsigned int index, bool in_vblank_irq, > + int *vpos, int *hpos, > + ktime_t *stime, ktime_t *etime, > + const struct drm_display_mode *mode) > { > struct drm_i915_private *dev_priv = to_i915(dev); > struct intel_crtc *crtc = to_intel_crtc(drm_crtc_from_index(dev, index)); > @@ -879,6 +885,109 @@ bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int index, > return true; > } > > +bool i915_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, > + unsigned int pipe, > + int *max_error, > + ktime_t *vblank_time, > + bool in_vblank_irq) > +{ > + struct timespec64 ts_etime, ts_vblank_time; > + ktime_t stime, etime; > + bool vbl_status; > + struct drm_crtc *crtc; > + const struct drm_display_mode *mode; > + struct drm_vblank_crtc *vblank = &dev->vblank[pipe]; > + int vpos, hpos, i; > + int delta_ns, duration_ns; > + > + crtc = drm_crtc_from_index(dev, pipe); > + > + if (pipe >= dev->num_crtcs || !crtc) { > + DRM_ERROR("Invalid crtc %u\n", pipe); > + return false; > + } > + > + if (drm_drv_uses_atomic_modeset(dev)) > + mode = &vblank->hwmode; > + else > + mode = &crtc->hwmode; > + > + /* If mode timing undefined, just return as no-op: > + * Happens during initial modesetting of a crtc. > + */ > + if (mode->crtc_clock == 0) { > + DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe); > + WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev)); > + > + return false; > + } > + > + /* Get current scanout position with system timestamp. > + * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times > + * if single query takes longer than max_error nanoseconds. > + * > + * This guarantees a tight bound on maximum error if > + * code gets preempted or delayed for some reason. > + */ > + for (i = 0; i < I915_TIMESTAMP_MAXRETRIES; i++) { > + /* > + * Get vertical and horizontal scanout position vpos, hpos, > + * and bounding timestamps stime, etime, pre/post query. > + */ > + vbl_status = i915_get_crtc_scanoutpos(dev, pipe, in_vblank_irq, > + &vpos, &hpos, &stime, > + &etime, mode); > + /* Return as no-op if scanout query unsupported or failed. */ > + if (!vbl_status) { > + DRM_DEBUG("crtc %u : scanoutpos query failed.\n", > + pipe); > + return false; > + } > + > + /* Compute uncertainty in timestamp of scanout position query. */ > + duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime); > + > + /* Accept result with < max_error nsecs timing uncertainty. */ > + if (duration_ns <= *max_error) > + break; > + } > + > + /* Noisy system timing? */ > + if (i == I915_TIMESTAMP_MAXRETRIES) { > + DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n", > + pipe, duration_ns/1000, *max_error/1000, i); > + } > + > + /* Return upper bound of timestamp precision error. */ > + *max_error = duration_ns; > + > + /* Convert scanout position into elapsed time at raw_time query > + * since start of scanout at first display scanline. delta_ns > + * can be negative if start of scanout hasn't happened yet. > + */ > + delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos), > + mode->crtc_clock); > + > + /* Subtract time delta from raw timestamp to get final > + * vblank_time timestamp for end of vblank. > + */ > + *vblank_time = ktime_sub_ns(etime, delta_ns); > + > + if (!drm_debug_enabled(DRM_UT_VBL)) > + return true; > + > + ts_etime = ktime_to_timespec64(etime); > + ts_vblank_time = ktime_to_timespec64(*vblank_time); > + > + DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n", > + pipe, hpos, vpos, > + (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000, > + (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000, > + duration_ns / 1000, i); > + > + return true; > +} > + > int intel_get_crtc_scanline(struct intel_crtc *crtc) > { > struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); > diff --git a/drivers/gpu/drm/i915/i915_irq.h b/drivers/gpu/drm/i915/i915_irq.h > index 812c47a9c2d6..5f7b133ce721 100644 > --- a/drivers/gpu/drm/i915/i915_irq.h > +++ b/drivers/gpu/drm/i915/i915_irq.h > @@ -101,10 +101,11 @@ void gen8_irq_power_well_post_enable(struct drm_i915_private *dev_priv, > void gen8_irq_power_well_pre_disable(struct drm_i915_private *dev_priv, > u8 pipe_mask); > > -bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe, > - bool in_vblank_irq, int *vpos, int *hpos, > - ktime_t *stime, ktime_t *etime, > - const struct drm_display_mode *mode); > +bool i915_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, > + unsigned int pipe, > + int *max_error, > + ktime_t *vblank_time, > + bool in_vblank_irq); > > u32 i915_get_vblank_counter(struct drm_crtc *crtc); > u32 g4x_get_vblank_counter(struct drm_crtc *crtc);
Hi Am 10.01.20 um 12:59 schrieb Jani Nikula: > On Fri, 10 Jan 2020, Thomas Zimmermann <tzimmermann@suse.de> wrote: >> The callback struct drm_driver.get_scanout_position() is deprecated in >> favor of struct drm_crtc_helper_funcs.get_scanout_position(). >> >> i915 doesn't use CRTC helpers. The patch duplicates the caller >> drm_calc_vbltimestamp_from_scanoutpos() for i915, such that the callback >> function is not needed. >> >> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> >> --- >> drivers/gpu/drm/i915/i915_drv.c | 3 +- >> drivers/gpu/drm/i915/i915_irq.c | 117 ++++++++++++++++++++++++++++++-- >> drivers/gpu/drm/i915/i915_irq.h | 9 +-- >> 3 files changed, 119 insertions(+), 10 deletions(-) > > Not really enthusiastic about the diffstat in a "cleanup" series. Well, the cleanup is about the content of drm_driver :) > > I wonder if you could add a generic helper version of > drm_calc_vbltimestamp_from_scanoutpos where you pass the > get_scanout_position function as a parameter. Both > drm_calc_vbltimestamp_from_scanoutpos and the new > i915_calc_vbltimestamp_from_scanoutpos would then be fairly thin > wrappers passing in the relevant get_scanout_position function. Of course. Will be in v2 of the series. Best regards Thomas > > This would reduce the almost identical duplication of the function in > i915. > > BR, > Jani. > >> >> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c >> index f7385abdd74b..4a0a7fb85c53 100644 >> --- a/drivers/gpu/drm/i915/i915_drv.c >> +++ b/drivers/gpu/drm/i915/i915_drv.c >> @@ -2769,8 +2769,7 @@ static struct drm_driver driver = { >> .gem_prime_export = i915_gem_prime_export, >> .gem_prime_import = i915_gem_prime_import, >> >> - .get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos, >> - .get_scanout_position = i915_get_crtc_scanoutpos, >> + .get_vblank_timestamp = i915_calc_vbltimestamp_from_scanoutpos, >> >> .dumb_create = i915_gem_dumb_create, >> .dumb_map_offset = i915_gem_dumb_mmap_offset, >> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c >> index afc6aad9bf8c..99d0c3b0feae 100644 >> --- a/drivers/gpu/drm/i915/i915_irq.c >> +++ b/drivers/gpu/drm/i915/i915_irq.c >> @@ -52,6 +52,11 @@ >> #include "i915_trace.h" >> #include "intel_pm.h" >> >> +/* Retry timestamp calculation up to 3 times to satisfy >> + * drm_timestamp_precision before giving up. >> + */ >> +#define I915_TIMESTAMP_MAXRETRIES 3 >> + >> /** >> * DOC: interrupt handling >> * >> @@ -762,10 +767,11 @@ static int __intel_get_crtc_scanline(struct intel_crtc *crtc) >> return (position + crtc->scanline_offset) % vtotal; >> } >> >> -bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int index, >> - bool in_vblank_irq, int *vpos, int *hpos, >> - ktime_t *stime, ktime_t *etime, >> - const struct drm_display_mode *mode) >> +static bool i915_get_crtc_scanoutpos(struct drm_device *dev, >> + unsigned int index, bool in_vblank_irq, >> + int *vpos, int *hpos, >> + ktime_t *stime, ktime_t *etime, >> + const struct drm_display_mode *mode) >> { >> struct drm_i915_private *dev_priv = to_i915(dev); >> struct intel_crtc *crtc = to_intel_crtc(drm_crtc_from_index(dev, index)); >> @@ -879,6 +885,109 @@ bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int index, >> return true; >> } >> >> +bool i915_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, >> + unsigned int pipe, >> + int *max_error, >> + ktime_t *vblank_time, >> + bool in_vblank_irq) >> +{ >> + struct timespec64 ts_etime, ts_vblank_time; >> + ktime_t stime, etime; >> + bool vbl_status; >> + struct drm_crtc *crtc; >> + const struct drm_display_mode *mode; >> + struct drm_vblank_crtc *vblank = &dev->vblank[pipe]; >> + int vpos, hpos, i; >> + int delta_ns, duration_ns; >> + >> + crtc = drm_crtc_from_index(dev, pipe); >> + >> + if (pipe >= dev->num_crtcs || !crtc) { >> + DRM_ERROR("Invalid crtc %u\n", pipe); >> + return false; >> + } >> + >> + if (drm_drv_uses_atomic_modeset(dev)) >> + mode = &vblank->hwmode; >> + else >> + mode = &crtc->hwmode; >> + >> + /* If mode timing undefined, just return as no-op: >> + * Happens during initial modesetting of a crtc. >> + */ >> + if (mode->crtc_clock == 0) { >> + DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe); >> + WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev)); >> + >> + return false; >> + } >> + >> + /* Get current scanout position with system timestamp. >> + * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times >> + * if single query takes longer than max_error nanoseconds. >> + * >> + * This guarantees a tight bound on maximum error if >> + * code gets preempted or delayed for some reason. >> + */ >> + for (i = 0; i < I915_TIMESTAMP_MAXRETRIES; i++) { >> + /* >> + * Get vertical and horizontal scanout position vpos, hpos, >> + * and bounding timestamps stime, etime, pre/post query. >> + */ >> + vbl_status = i915_get_crtc_scanoutpos(dev, pipe, in_vblank_irq, >> + &vpos, &hpos, &stime, >> + &etime, mode); >> + /* Return as no-op if scanout query unsupported or failed. */ >> + if (!vbl_status) { >> + DRM_DEBUG("crtc %u : scanoutpos query failed.\n", >> + pipe); >> + return false; >> + } >> + >> + /* Compute uncertainty in timestamp of scanout position query. */ >> + duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime); >> + >> + /* Accept result with < max_error nsecs timing uncertainty. */ >> + if (duration_ns <= *max_error) >> + break; >> + } >> + >> + /* Noisy system timing? */ >> + if (i == I915_TIMESTAMP_MAXRETRIES) { >> + DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n", >> + pipe, duration_ns/1000, *max_error/1000, i); >> + } >> + >> + /* Return upper bound of timestamp precision error. */ >> + *max_error = duration_ns; >> + >> + /* Convert scanout position into elapsed time at raw_time query >> + * since start of scanout at first display scanline. delta_ns >> + * can be negative if start of scanout hasn't happened yet. >> + */ >> + delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos), >> + mode->crtc_clock); >> + >> + /* Subtract time delta from raw timestamp to get final >> + * vblank_time timestamp for end of vblank. >> + */ >> + *vblank_time = ktime_sub_ns(etime, delta_ns); >> + >> + if (!drm_debug_enabled(DRM_UT_VBL)) >> + return true; >> + >> + ts_etime = ktime_to_timespec64(etime); >> + ts_vblank_time = ktime_to_timespec64(*vblank_time); >> + >> + DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n", >> + pipe, hpos, vpos, >> + (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000, >> + (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000, >> + duration_ns / 1000, i); >> + >> + return true; >> +} >> + >> int intel_get_crtc_scanline(struct intel_crtc *crtc) >> { >> struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); >> diff --git a/drivers/gpu/drm/i915/i915_irq.h b/drivers/gpu/drm/i915/i915_irq.h >> index 812c47a9c2d6..5f7b133ce721 100644 >> --- a/drivers/gpu/drm/i915/i915_irq.h >> +++ b/drivers/gpu/drm/i915/i915_irq.h >> @@ -101,10 +101,11 @@ void gen8_irq_power_well_post_enable(struct drm_i915_private *dev_priv, >> void gen8_irq_power_well_pre_disable(struct drm_i915_private *dev_priv, >> u8 pipe_mask); >> >> -bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe, >> - bool in_vblank_irq, int *vpos, int *hpos, >> - ktime_t *stime, ktime_t *etime, >> - const struct drm_display_mode *mode); >> +bool i915_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, >> + unsigned int pipe, >> + int *max_error, >> + ktime_t *vblank_time, >> + bool in_vblank_irq); >> >> u32 i915_get_vblank_counter(struct drm_crtc *crtc); >> u32 g4x_get_vblank_counter(struct drm_crtc *crtc); >
On Fri, 10 Jan 2020, Thomas Zimmermann <tzimmermann@suse.de> wrote: > Hi > > Am 10.01.20 um 12:59 schrieb Jani Nikula: >> On Fri, 10 Jan 2020, Thomas Zimmermann <tzimmermann@suse.de> wrote: >>> The callback struct drm_driver.get_scanout_position() is deprecated in >>> favor of struct drm_crtc_helper_funcs.get_scanout_position(). >>> >>> i915 doesn't use CRTC helpers. The patch duplicates the caller >>> drm_calc_vbltimestamp_from_scanoutpos() for i915, such that the callback >>> function is not needed. >>> >>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> >>> --- >>> drivers/gpu/drm/i915/i915_drv.c | 3 +- >>> drivers/gpu/drm/i915/i915_irq.c | 117 ++++++++++++++++++++++++++++++-- >>> drivers/gpu/drm/i915/i915_irq.h | 9 +-- >>> 3 files changed, 119 insertions(+), 10 deletions(-) >> >> Not really enthusiastic about the diffstat in a "cleanup" series. > > Well, the cleanup is about the content of drm_driver :) > >> >> I wonder if you could add a generic helper version of >> drm_calc_vbltimestamp_from_scanoutpos where you pass the >> get_scanout_position function as a parameter. Both >> drm_calc_vbltimestamp_from_scanoutpos and the new >> i915_calc_vbltimestamp_from_scanoutpos would then be fairly thin >> wrappers passing in the relevant get_scanout_position function. > > Of course. Will be in v2 of the series. Please give Ville (Cc'd) a moment before sending v2 in case he wants to chime in on this. Thanks, Jani. > > Best regards > Thomas > >> >> This would reduce the almost identical duplication of the function in >> i915. >> >> BR, >> Jani. >> >>> >>> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c >>> index f7385abdd74b..4a0a7fb85c53 100644 >>> --- a/drivers/gpu/drm/i915/i915_drv.c >>> +++ b/drivers/gpu/drm/i915/i915_drv.c >>> @@ -2769,8 +2769,7 @@ static struct drm_driver driver = { >>> .gem_prime_export = i915_gem_prime_export, >>> .gem_prime_import = i915_gem_prime_import, >>> >>> - .get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos, >>> - .get_scanout_position = i915_get_crtc_scanoutpos, >>> + .get_vblank_timestamp = i915_calc_vbltimestamp_from_scanoutpos, >>> >>> .dumb_create = i915_gem_dumb_create, >>> .dumb_map_offset = i915_gem_dumb_mmap_offset, >>> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c >>> index afc6aad9bf8c..99d0c3b0feae 100644 >>> --- a/drivers/gpu/drm/i915/i915_irq.c >>> +++ b/drivers/gpu/drm/i915/i915_irq.c >>> @@ -52,6 +52,11 @@ >>> #include "i915_trace.h" >>> #include "intel_pm.h" >>> >>> +/* Retry timestamp calculation up to 3 times to satisfy >>> + * drm_timestamp_precision before giving up. >>> + */ >>> +#define I915_TIMESTAMP_MAXRETRIES 3 >>> + >>> /** >>> * DOC: interrupt handling >>> * >>> @@ -762,10 +767,11 @@ static int __intel_get_crtc_scanline(struct intel_crtc *crtc) >>> return (position + crtc->scanline_offset) % vtotal; >>> } >>> >>> -bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int index, >>> - bool in_vblank_irq, int *vpos, int *hpos, >>> - ktime_t *stime, ktime_t *etime, >>> - const struct drm_display_mode *mode) >>> +static bool i915_get_crtc_scanoutpos(struct drm_device *dev, >>> + unsigned int index, bool in_vblank_irq, >>> + int *vpos, int *hpos, >>> + ktime_t *stime, ktime_t *etime, >>> + const struct drm_display_mode *mode) >>> { >>> struct drm_i915_private *dev_priv = to_i915(dev); >>> struct intel_crtc *crtc = to_intel_crtc(drm_crtc_from_index(dev, index)); >>> @@ -879,6 +885,109 @@ bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int index, >>> return true; >>> } >>> >>> +bool i915_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, >>> + unsigned int pipe, >>> + int *max_error, >>> + ktime_t *vblank_time, >>> + bool in_vblank_irq) >>> +{ >>> + struct timespec64 ts_etime, ts_vblank_time; >>> + ktime_t stime, etime; >>> + bool vbl_status; >>> + struct drm_crtc *crtc; >>> + const struct drm_display_mode *mode; >>> + struct drm_vblank_crtc *vblank = &dev->vblank[pipe]; >>> + int vpos, hpos, i; >>> + int delta_ns, duration_ns; >>> + >>> + crtc = drm_crtc_from_index(dev, pipe); >>> + >>> + if (pipe >= dev->num_crtcs || !crtc) { >>> + DRM_ERROR("Invalid crtc %u\n", pipe); >>> + return false; >>> + } >>> + >>> + if (drm_drv_uses_atomic_modeset(dev)) >>> + mode = &vblank->hwmode; >>> + else >>> + mode = &crtc->hwmode; >>> + >>> + /* If mode timing undefined, just return as no-op: >>> + * Happens during initial modesetting of a crtc. >>> + */ >>> + if (mode->crtc_clock == 0) { >>> + DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe); >>> + WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev)); >>> + >>> + return false; >>> + } >>> + >>> + /* Get current scanout position with system timestamp. >>> + * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times >>> + * if single query takes longer than max_error nanoseconds. >>> + * >>> + * This guarantees a tight bound on maximum error if >>> + * code gets preempted or delayed for some reason. >>> + */ >>> + for (i = 0; i < I915_TIMESTAMP_MAXRETRIES; i++) { >>> + /* >>> + * Get vertical and horizontal scanout position vpos, hpos, >>> + * and bounding timestamps stime, etime, pre/post query. >>> + */ >>> + vbl_status = i915_get_crtc_scanoutpos(dev, pipe, in_vblank_irq, >>> + &vpos, &hpos, &stime, >>> + &etime, mode); >>> + /* Return as no-op if scanout query unsupported or failed. */ >>> + if (!vbl_status) { >>> + DRM_DEBUG("crtc %u : scanoutpos query failed.\n", >>> + pipe); >>> + return false; >>> + } >>> + >>> + /* Compute uncertainty in timestamp of scanout position query. */ >>> + duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime); >>> + >>> + /* Accept result with < max_error nsecs timing uncertainty. */ >>> + if (duration_ns <= *max_error) >>> + break; >>> + } >>> + >>> + /* Noisy system timing? */ >>> + if (i == I915_TIMESTAMP_MAXRETRIES) { >>> + DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n", >>> + pipe, duration_ns/1000, *max_error/1000, i); >>> + } >>> + >>> + /* Return upper bound of timestamp precision error. */ >>> + *max_error = duration_ns; >>> + >>> + /* Convert scanout position into elapsed time at raw_time query >>> + * since start of scanout at first display scanline. delta_ns >>> + * can be negative if start of scanout hasn't happened yet. >>> + */ >>> + delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos), >>> + mode->crtc_clock); >>> + >>> + /* Subtract time delta from raw timestamp to get final >>> + * vblank_time timestamp for end of vblank. >>> + */ >>> + *vblank_time = ktime_sub_ns(etime, delta_ns); >>> + >>> + if (!drm_debug_enabled(DRM_UT_VBL)) >>> + return true; >>> + >>> + ts_etime = ktime_to_timespec64(etime); >>> + ts_vblank_time = ktime_to_timespec64(*vblank_time); >>> + >>> + DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n", >>> + pipe, hpos, vpos, >>> + (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000, >>> + (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000, >>> + duration_ns / 1000, i); >>> + >>> + return true; >>> +} >>> + >>> int intel_get_crtc_scanline(struct intel_crtc *crtc) >>> { >>> struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); >>> diff --git a/drivers/gpu/drm/i915/i915_irq.h b/drivers/gpu/drm/i915/i915_irq.h >>> index 812c47a9c2d6..5f7b133ce721 100644 >>> --- a/drivers/gpu/drm/i915/i915_irq.h >>> +++ b/drivers/gpu/drm/i915/i915_irq.h >>> @@ -101,10 +101,11 @@ void gen8_irq_power_well_post_enable(struct drm_i915_private *dev_priv, >>> void gen8_irq_power_well_pre_disable(struct drm_i915_private *dev_priv, >>> u8 pipe_mask); >>> >>> -bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe, >>> - bool in_vblank_irq, int *vpos, int *hpos, >>> - ktime_t *stime, ktime_t *etime, >>> - const struct drm_display_mode *mode); >>> +bool i915_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, >>> + unsigned int pipe, >>> + int *max_error, >>> + ktime_t *vblank_time, >>> + bool in_vblank_irq); >>> >>> u32 i915_get_vblank_counter(struct drm_crtc *crtc); >>> u32 g4x_get_vblank_counter(struct drm_crtc *crtc); >>
On Fri, Jan 10, 2020 at 03:56:06PM +0200, Jani Nikula wrote: > On Fri, 10 Jan 2020, Thomas Zimmermann <tzimmermann@suse.de> wrote: > > Hi > > > > Am 10.01.20 um 12:59 schrieb Jani Nikula: > >> On Fri, 10 Jan 2020, Thomas Zimmermann <tzimmermann@suse.de> wrote: > >>> The callback struct drm_driver.get_scanout_position() is deprecated in > >>> favor of struct drm_crtc_helper_funcs.get_scanout_position(). > >>> > >>> i915 doesn't use CRTC helpers. The patch duplicates the caller > >>> drm_calc_vbltimestamp_from_scanoutpos() for i915, such that the callback > >>> function is not needed. > >>> > >>> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> > >>> --- > >>> drivers/gpu/drm/i915/i915_drv.c | 3 +- > >>> drivers/gpu/drm/i915/i915_irq.c | 117 ++++++++++++++++++++++++++++++-- > >>> drivers/gpu/drm/i915/i915_irq.h | 9 +-- > >>> 3 files changed, 119 insertions(+), 10 deletions(-) > >> > >> Not really enthusiastic about the diffstat in a "cleanup" series. > > > > Well, the cleanup is about the content of drm_driver :) > > > >> > >> I wonder if you could add a generic helper version of > >> drm_calc_vbltimestamp_from_scanoutpos where you pass the > >> get_scanout_position function as a parameter. Both > >> drm_calc_vbltimestamp_from_scanoutpos and the new > >> i915_calc_vbltimestamp_from_scanoutpos would then be fairly thin > >> wrappers passing in the relevant get_scanout_position function. > > > > Of course. Will be in v2 of the series. > > Please give Ville (Cc'd) a moment before sending v2 in case he wants to > chime in on this. Passing the function pointer was one option I considered for this a while back. Can't remeber what other solutions I condsidered. But I guess I didn't like any of them enough to make an actual patch.
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index f7385abdd74b..4a0a7fb85c53 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -2769,8 +2769,7 @@ static struct drm_driver driver = { .gem_prime_export = i915_gem_prime_export, .gem_prime_import = i915_gem_prime_import, - .get_vblank_timestamp = drm_calc_vbltimestamp_from_scanoutpos, - .get_scanout_position = i915_get_crtc_scanoutpos, + .get_vblank_timestamp = i915_calc_vbltimestamp_from_scanoutpos, .dumb_create = i915_gem_dumb_create, .dumb_map_offset = i915_gem_dumb_mmap_offset, diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c index afc6aad9bf8c..99d0c3b0feae 100644 --- a/drivers/gpu/drm/i915/i915_irq.c +++ b/drivers/gpu/drm/i915/i915_irq.c @@ -52,6 +52,11 @@ #include "i915_trace.h" #include "intel_pm.h" +/* Retry timestamp calculation up to 3 times to satisfy + * drm_timestamp_precision before giving up. + */ +#define I915_TIMESTAMP_MAXRETRIES 3 + /** * DOC: interrupt handling * @@ -762,10 +767,11 @@ static int __intel_get_crtc_scanline(struct intel_crtc *crtc) return (position + crtc->scanline_offset) % vtotal; } -bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int index, - bool in_vblank_irq, int *vpos, int *hpos, - ktime_t *stime, ktime_t *etime, - const struct drm_display_mode *mode) +static bool i915_get_crtc_scanoutpos(struct drm_device *dev, + unsigned int index, bool in_vblank_irq, + int *vpos, int *hpos, + ktime_t *stime, ktime_t *etime, + const struct drm_display_mode *mode) { struct drm_i915_private *dev_priv = to_i915(dev); struct intel_crtc *crtc = to_intel_crtc(drm_crtc_from_index(dev, index)); @@ -879,6 +885,109 @@ bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int index, return true; } +bool i915_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, + unsigned int pipe, + int *max_error, + ktime_t *vblank_time, + bool in_vblank_irq) +{ + struct timespec64 ts_etime, ts_vblank_time; + ktime_t stime, etime; + bool vbl_status; + struct drm_crtc *crtc; + const struct drm_display_mode *mode; + struct drm_vblank_crtc *vblank = &dev->vblank[pipe]; + int vpos, hpos, i; + int delta_ns, duration_ns; + + crtc = drm_crtc_from_index(dev, pipe); + + if (pipe >= dev->num_crtcs || !crtc) { + DRM_ERROR("Invalid crtc %u\n", pipe); + return false; + } + + if (drm_drv_uses_atomic_modeset(dev)) + mode = &vblank->hwmode; + else + mode = &crtc->hwmode; + + /* If mode timing undefined, just return as no-op: + * Happens during initial modesetting of a crtc. + */ + if (mode->crtc_clock == 0) { + DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe); + WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev)); + + return false; + } + + /* Get current scanout position with system timestamp. + * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times + * if single query takes longer than max_error nanoseconds. + * + * This guarantees a tight bound on maximum error if + * code gets preempted or delayed for some reason. + */ + for (i = 0; i < I915_TIMESTAMP_MAXRETRIES; i++) { + /* + * Get vertical and horizontal scanout position vpos, hpos, + * and bounding timestamps stime, etime, pre/post query. + */ + vbl_status = i915_get_crtc_scanoutpos(dev, pipe, in_vblank_irq, + &vpos, &hpos, &stime, + &etime, mode); + /* Return as no-op if scanout query unsupported or failed. */ + if (!vbl_status) { + DRM_DEBUG("crtc %u : scanoutpos query failed.\n", + pipe); + return false; + } + + /* Compute uncertainty in timestamp of scanout position query. */ + duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime); + + /* Accept result with < max_error nsecs timing uncertainty. */ + if (duration_ns <= *max_error) + break; + } + + /* Noisy system timing? */ + if (i == I915_TIMESTAMP_MAXRETRIES) { + DRM_DEBUG("crtc %u: Noisy timestamp %d us > %d us [%d reps].\n", + pipe, duration_ns/1000, *max_error/1000, i); + } + + /* Return upper bound of timestamp precision error. */ + *max_error = duration_ns; + + /* Convert scanout position into elapsed time at raw_time query + * since start of scanout at first display scanline. delta_ns + * can be negative if start of scanout hasn't happened yet. + */ + delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos), + mode->crtc_clock); + + /* Subtract time delta from raw timestamp to get final + * vblank_time timestamp for end of vblank. + */ + *vblank_time = ktime_sub_ns(etime, delta_ns); + + if (!drm_debug_enabled(DRM_UT_VBL)) + return true; + + ts_etime = ktime_to_timespec64(etime); + ts_vblank_time = ktime_to_timespec64(*vblank_time); + + DRM_DEBUG_VBL("crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n", + pipe, hpos, vpos, + (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000, + (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000, + duration_ns / 1000, i); + + return true; +} + int intel_get_crtc_scanline(struct intel_crtc *crtc) { struct drm_i915_private *dev_priv = to_i915(crtc->base.dev); diff --git a/drivers/gpu/drm/i915/i915_irq.h b/drivers/gpu/drm/i915/i915_irq.h index 812c47a9c2d6..5f7b133ce721 100644 --- a/drivers/gpu/drm/i915/i915_irq.h +++ b/drivers/gpu/drm/i915/i915_irq.h @@ -101,10 +101,11 @@ void gen8_irq_power_well_post_enable(struct drm_i915_private *dev_priv, void gen8_irq_power_well_pre_disable(struct drm_i915_private *dev_priv, u8 pipe_mask); -bool i915_get_crtc_scanoutpos(struct drm_device *dev, unsigned int pipe, - bool in_vblank_irq, int *vpos, int *hpos, - ktime_t *stime, ktime_t *etime, - const struct drm_display_mode *mode); +bool i915_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, + unsigned int pipe, + int *max_error, + ktime_t *vblank_time, + bool in_vblank_irq); u32 i915_get_vblank_counter(struct drm_crtc *crtc); u32 g4x_get_vblank_counter(struct drm_crtc *crtc);
The callback struct drm_driver.get_scanout_position() is deprecated in favor of struct drm_crtc_helper_funcs.get_scanout_position(). i915 doesn't use CRTC helpers. The patch duplicates the caller drm_calc_vbltimestamp_from_scanoutpos() for i915, such that the callback function is not needed. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> --- drivers/gpu/drm/i915/i915_drv.c | 3 +- drivers/gpu/drm/i915/i915_irq.c | 117 ++++++++++++++++++++++++++++++-- drivers/gpu/drm/i915/i915_irq.h | 9 +-- 3 files changed, 119 insertions(+), 10 deletions(-)