| Message ID | 20190907110735.10302-9-animesh.manna@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | DSB enablement. | expand |
On 9/7/2019 4:37 PM, Animesh Manna wrote: > The lifetime of command buffer can be controlled by the dsb user > throuh refcount. Added refcount mechanism is dsb get/put call > which create/destroy dsb context. > > Cc: Jani Nikula <jani.nikula@intel.com> > Cc: Shashank Sharma <shashank.sharma@intel.com> > Signed-off-by: Animesh Manna <animesh.manna@intel.com> > --- > drivers/gpu/drm/i915/display/intel_dsb.c | 22 ++++++++++++++++------ > drivers/gpu/drm/i915/display/intel_dsb.h | 1 + > 2 files changed, 17 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c > index 853685751540..b951a6b5264a 100644 > --- a/drivers/gpu/drm/i915/display/intel_dsb.c > +++ b/drivers/gpu/drm/i915/display/intel_dsb.c > @@ -78,7 +78,12 @@ intel_dsb_get(struct intel_crtc *crtc) > struct intel_dsb *dsb = &crtc->dsb; > intel_wakeref_t wakeref; > > - if ((!HAS_DSB(i915)) || dsb->cmd_buf) > + if (!HAS_DSB(i915)) > + return dsb; > + > + atomic_inc(&dsb->refcount); > + As discussed we are not solving any problem with reference counting, rather, we are adding a complexity here. It may be useful, when we are extending single instance of DSB to DSB pool but not right now. I would say we drop this patch all together, and just have the simple implementation now. - Shashank > + if (dsb->cmd_buf) > return dsb; > > dsb->id = DSB1; > @@ -94,6 +99,7 @@ intel_dsb_get(struct intel_crtc *crtc) > if (IS_ERR(vma)) { > DRM_ERROR("Vma creation failed.\n"); > i915_gem_object_put(obj); > + atomic_dec(&dsb->refcount); > goto err; > } > > @@ -102,6 +108,7 @@ intel_dsb_get(struct intel_crtc *crtc) > DRM_ERROR("Command buffer creation failed.\n"); > i915_vma_unpin_and_release(&vma, 0); > dsb->cmd_buf = NULL; > + atomic_dec(&dsb->refcount); > goto err; > } > dsb->vma = vma; > @@ -121,11 +128,14 @@ void intel_dsb_put(struct intel_dsb *dsb) > return; > > if (dsb->cmd_buf) { > - mutex_lock(&i915->drm.struct_mutex); > - i915_gem_object_unpin_map(dsb->vma->obj); > - i915_vma_unpin_and_release(&dsb->vma, 0); > - dsb->cmd_buf = NULL; > - mutex_unlock(&i915->drm.struct_mutex); > + atomic_dec(&dsb->refcount); > + if (!atomic_read(&dsb->refcount)) { > + mutex_lock(&i915->drm.struct_mutex); > + i915_gem_object_unpin_map(dsb->vma->obj); > + i915_vma_unpin_and_release(&dsb->vma, 0); > + dsb->cmd_buf = NULL; > + mutex_unlock(&i915->drm.struct_mutex); > + } > } > } > > diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h b/drivers/gpu/drm/i915/display/intel_dsb.h > index 7389c8c5b665..dca4e632dd3c 100644 > --- a/drivers/gpu/drm/i915/display/intel_dsb.h > +++ b/drivers/gpu/drm/i915/display/intel_dsb.h > @@ -20,6 +20,7 @@ enum dsb_id { > }; > > struct intel_dsb { > + atomic_t refcount; > enum dsb_id id; > u32 *cmd_buf; > struct i915_vma *vma;
On 9/9/2019 6:51 PM, Sharma, Shashank wrote: > > On 9/7/2019 4:37 PM, Animesh Manna wrote: >> The lifetime of command buffer can be controlled by the dsb user >> throuh refcount. Added refcount mechanism is dsb get/put call >> which create/destroy dsb context. >> >> Cc: Jani Nikula <jani.nikula@intel.com> >> Cc: Shashank Sharma <shashank.sharma@intel.com> >> Signed-off-by: Animesh Manna <animesh.manna@intel.com> >> --- >> drivers/gpu/drm/i915/display/intel_dsb.c | 22 ++++++++++++++++------ >> drivers/gpu/drm/i915/display/intel_dsb.h | 1 + >> 2 files changed, 17 insertions(+), 6 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c >> b/drivers/gpu/drm/i915/display/intel_dsb.c >> index 853685751540..b951a6b5264a 100644 >> --- a/drivers/gpu/drm/i915/display/intel_dsb.c >> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c >> @@ -78,7 +78,12 @@ intel_dsb_get(struct intel_crtc *crtc) >> struct intel_dsb *dsb = &crtc->dsb; >> intel_wakeref_t wakeref; >> - if ((!HAS_DSB(i915)) || dsb->cmd_buf) >> + if (!HAS_DSB(i915)) >> + return dsb; >> + >> + atomic_inc(&dsb->refcount); >> + > > As discussed we are not solving any problem with reference counting, > rather, we are adding a complexity here. It may be useful, when we are > extending single instance of DSB to DSB pool but not right now. > > I would say we drop this patch all together, and just have the simple > implementation now. Tried to have synchronization in single thread multiple user scenario through ref-count mechanism, but can be taken in phased approach in future. Regards, Animesh
diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c index 853685751540..b951a6b5264a 100644 --- a/drivers/gpu/drm/i915/display/intel_dsb.c +++ b/drivers/gpu/drm/i915/display/intel_dsb.c @@ -78,7 +78,12 @@ intel_dsb_get(struct intel_crtc *crtc) struct intel_dsb *dsb = &crtc->dsb; intel_wakeref_t wakeref; - if ((!HAS_DSB(i915)) || dsb->cmd_buf) + if (!HAS_DSB(i915)) + return dsb; + + atomic_inc(&dsb->refcount); + + if (dsb->cmd_buf) return dsb; dsb->id = DSB1; @@ -94,6 +99,7 @@ intel_dsb_get(struct intel_crtc *crtc) if (IS_ERR(vma)) { DRM_ERROR("Vma creation failed.\n"); i915_gem_object_put(obj); + atomic_dec(&dsb->refcount); goto err; } @@ -102,6 +108,7 @@ intel_dsb_get(struct intel_crtc *crtc) DRM_ERROR("Command buffer creation failed.\n"); i915_vma_unpin_and_release(&vma, 0); dsb->cmd_buf = NULL; + atomic_dec(&dsb->refcount); goto err; } dsb->vma = vma; @@ -121,11 +128,14 @@ void intel_dsb_put(struct intel_dsb *dsb) return; if (dsb->cmd_buf) { - mutex_lock(&i915->drm.struct_mutex); - i915_gem_object_unpin_map(dsb->vma->obj); - i915_vma_unpin_and_release(&dsb->vma, 0); - dsb->cmd_buf = NULL; - mutex_unlock(&i915->drm.struct_mutex); + atomic_dec(&dsb->refcount); + if (!atomic_read(&dsb->refcount)) { + mutex_lock(&i915->drm.struct_mutex); + i915_gem_object_unpin_map(dsb->vma->obj); + i915_vma_unpin_and_release(&dsb->vma, 0); + dsb->cmd_buf = NULL; + mutex_unlock(&i915->drm.struct_mutex); + } } } diff --git a/drivers/gpu/drm/i915/display/intel_dsb.h b/drivers/gpu/drm/i915/display/intel_dsb.h index 7389c8c5b665..dca4e632dd3c 100644 --- a/drivers/gpu/drm/i915/display/intel_dsb.h +++ b/drivers/gpu/drm/i915/display/intel_dsb.h @@ -20,6 +20,7 @@ enum dsb_id { }; struct intel_dsb { + atomic_t refcount; enum dsb_id id; u32 *cmd_buf; struct i915_vma *vma;
The lifetime of command buffer can be controlled by the dsb user throuh refcount. Added refcount mechanism is dsb get/put call which create/destroy dsb context. Cc: Jani Nikula <jani.nikula@intel.com> Cc: Shashank Sharma <shashank.sharma@intel.com> Signed-off-by: Animesh Manna <animesh.manna@intel.com> --- drivers/gpu/drm/i915/display/intel_dsb.c | 22 ++++++++++++++++------ drivers/gpu/drm/i915/display/intel_dsb.h | 1 + 2 files changed, 17 insertions(+), 6 deletions(-)