On Thu, Aug 02, 2018 at 08:09:51AM -0300, Gustavo Padovan wrote: > Hi Haneen, > > On Thu, Aug 02, 2018 at 04:10:26AM +0300, Haneen Mohammed wrote: > > This patch implement the necessary functions to compute and add CRCs > > entries: > > > > - Implement the set_crc_source() callback. > > - Compute CRC using crc32 on the visible part of the framebuffer. > > - Use ordered workqueue per output to compute and add CRC at the end > > of a vblank. > > - Use appropriate synchronization methods since the CRC computation must > > be atomic wrt the generated vblank event for a given atomic update, by > > using spinlock across atomic_begin/atomic_flush to wrap the event > > handling code completely and match the flip event with the CRC. > > > > Since vkms_crc_work_handle() can sleep, spinlock can't be acquired > > while accessing vkms_output->primary_crc to compute CRC. > > To make sure the data is updated and released without conflict with > > the vkms_crc_work_handle(), the work_struct is flushed @crtc_destroy > > and the data is updated before scheduling the work handle again, as > > follow: > > I'm not sure I get why this is a spinlock and not a mutex. With the > later you are able to sleep. Also, your spinlock held through the whole > atomic commit (from the begin to flush) which seems too much time for > busy waiting. Or am I missing something here? I expressed some of the same concerns here: https://lists.freedesktop.org/archives/dri-devel/2018-July/183584.html The tl;dr is that the spinlock is required so we can acquire it in the vblank hrtimer. It is held across begin/flush to prevent sending vblank eventss until the crc has been fully calculated for the frame. More details in the thread, ofc. Sean > > Gustavo > > > > > * CRC data update: > > 1- store vkms_crc_data {fb, src} per plane_state > > 2- @plane_duplicate_state -> allocate vkms_crc_data > > 3- during atomic commit (@atomic_update) -> > > a) copy {fb, src} to plane_state->crc_data > > b) get reference to fb, > > 3- @plane_destroy_state -> a) if (fb refcount) remove reference to fb > > b) deallocate crc_data > > > > * Atomic Commit: > > 1- vkms_plane_atomic_check > > 2- vkms_prepare_fb -> vmap vkms_gem_obj->vaddr > > 3- atomic_begin -> hold crc spinlock > > 4- atomic_plane_update -> a) update vkms_output->primary_crc > > b) get reference to fb > > 5- atomic_flush -> a) send vblank event while holding event_lock > > b) release crc spinlock > > > > * hrtimer regular callback: > > 1- hold crc spinlock > > 2- drm_crtc_handle_vblank() > > 3- queue vkms_crc_work_handle > > 4- release crc spinlock > > > > * cleanup: > > 1- @cleanup_fb ->vunmap vkms_gem_obj->vaddr > > 2- @crtc_destroy -> flush work struct > > 3- @plane_destroy -> a) if (fb refcount) remove reference to fb > > b) deallocate crc_data > > > > Signed-off-by: Haneen Mohammed <hamohammed.sa@xxxxxxxxx> > > --- > > Changes in v2: > > - remove vkms_crc_data for primary plane from vkms_output > > and access it from vkms_plane_state instead. > > - flush crc_workq in vkms_set_crc_source before changing out->enabled > > value. > > > > drivers/gpu/drm/vkms/Makefile | 2 +- > > drivers/gpu/drm/vkms/vkms_crc.c | 95 +++++++++++++++++++++++++++++++ > > drivers/gpu/drm/vkms/vkms_crtc.c | 56 +++++++++++++++--- > > drivers/gpu/drm/vkms/vkms_drv.c | 1 + > > drivers/gpu/drm/vkms/vkms_drv.h | 21 +++++++ > > drivers/gpu/drm/vkms/vkms_plane.c | 30 ++++++++++ > > 6 files changed, 196 insertions(+), 9 deletions(-) > > create mode 100644 drivers/gpu/drm/vkms/vkms_crc.c > > > > diff --git a/drivers/gpu/drm/vkms/Makefile b/drivers/gpu/drm/vkms/Makefile > > index 986297da51bf..37966914f70b 100644 > > --- a/drivers/gpu/drm/vkms/Makefile > > +++ b/drivers/gpu/drm/vkms/Makefile > > @@ -1,3 +1,3 @@ > > -vkms-y := vkms_drv.o vkms_plane.o vkms_output.o vkms_crtc.o vkms_gem.o > > +vkms-y := vkms_drv.o vkms_plane.o vkms_output.o vkms_crtc.o vkms_gem.o vkms_crc.o > > > > obj-$(CONFIG_DRM_VKMS) += vkms.o > > diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c > > new file mode 100644 > > index 000000000000..9b909221943f > > --- /dev/null > > +++ b/drivers/gpu/drm/vkms/vkms_crc.c > > @@ -0,0 +1,95 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > +#include "vkms_drv.h" > > +#include <linux/crc32.h> > > +#include <drm/drm_gem_framebuffer_helper.h> > > + > > +static uint32_t _vkms_get_crc(struct vkms_crc_data *crc_data) > > +{ > > + struct drm_framebuffer *fb = &crc_data->fb; > > + struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0); > > + struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(gem_obj); > > + u32 crc = 0; > > + int i = 0; > > + unsigned int x = crc_data->src.x1 >> 16; > > + unsigned int y = crc_data->src.y1 >> 16; > > + unsigned int height = drm_rect_height(&crc_data->src) >> 16; > > + unsigned int width = drm_rect_width(&crc_data->src) >> 16; > > + unsigned int cpp = fb->format->cpp[0]; > > + unsigned int src_offset; > > + unsigned int size_byte = width * cpp; > > + void *vaddr; > > + > > + mutex_lock(&vkms_obj->pages_lock); > > + vaddr = vkms_obj->vaddr; > > + if (WARN_ON(!vaddr)) > > + return crc; > > + > > + for (i = y; i < y + height; i++) { > > + src_offset = fb->offsets[0] + (i * fb->pitches[0]) + (x * cpp); > > + crc = crc32_le(crc, vaddr + src_offset, size_byte); > > + } > > + mutex_unlock(&vkms_obj->pages_lock); > > + > > + return crc; > > +} > > + > > +void vkms_crc_work_handle(struct work_struct *work) > > +{ > > + struct vkms_crtc_state *crtc_state = container_of(work, > > + struct vkms_crtc_state, > > + crc_work); > > + struct drm_crtc *crtc = crtc_state->base.crtc; > > + struct vkms_output *out = drm_crtc_to_vkms_output(crtc); > > + struct vkms_device *vdev = container_of(out, struct vkms_device, > > + output); > > + struct vkms_crc_data *primary_crc = NULL; > > + struct drm_plane *plane; > > + > > + u32 crc32 = 0; > > + > > + drm_for_each_plane(plane, &vdev->drm) { > > + struct vkms_plane_state *vplane_state; > > + struct vkms_crc_data *crc_data; > > + > > + vplane_state = to_vkms_plane_state(plane->state); > > + crc_data = vplane_state->crc_data; > > + > > + if (drm_framebuffer_read_refcount(&crc_data->fb) == 0) > > + continue; > > + > > + if (plane->type == DRM_PLANE_TYPE_PRIMARY) { > > + primary_crc = crc_data; > > + break; > > + } > > + } > > + > > + if (primary_crc) > > + crc32 = _vkms_get_crc(primary_crc); > > + > > + drm_crtc_add_crc_entry(crtc, true, crtc_state->n_frame, &crc32); > > +} > > + > > +int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name, > > + size_t *values_cnt) > > +{ > > + struct vkms_output *out = drm_crtc_to_vkms_output(crtc); > > + bool enabled = false; > > + unsigned long flags; > > + int ret = 0; > > + > > + if (src_name && strcmp(src_name, "auto") == 0) > > + enabled = true; > > + else if (src_name) > > + ret = -EINVAL; > > + > > + *values_cnt = 1; > > + > > + /* make sure nothing is scheduled on crtc workq */ > > + flush_workqueue(out->crc_workq); > > + > > + spin_lock_irqsave(&out->lock, flags); > > + out->crc_enabled = enabled; > > + spin_unlock_irqrestore(&out->lock, flags); > > + > > + return ret; > > +} > > diff --git a/drivers/gpu/drm/vkms/vkms_crtc.c b/drivers/gpu/drm/vkms/vkms_crtc.c > > index 26babb85ca77..a6c080d7f7ae 100644 > > --- a/drivers/gpu/drm/vkms/vkms_crtc.c > > +++ b/drivers/gpu/drm/vkms/vkms_crtc.c > > @@ -10,18 +10,33 @@ > > #include <drm/drm_atomic_helper.h> > > #include <drm/drm_crtc_helper.h> > > > > -static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer) > > +static void _vblank_handle(struct vkms_output *output) > > { > > - struct vkms_output *output = container_of(timer, struct vkms_output, > > - vblank_hrtimer); > > struct drm_crtc *crtc = &output->crtc; > > - int ret_overrun; > > + struct vkms_crtc_state *state = to_vkms_crtc_state(crtc->state); > > bool ret; > > > > + spin_lock(&output->lock); > > ret = drm_crtc_handle_vblank(crtc); > > if (!ret) > > DRM_ERROR("vkms failure on handling vblank"); > > > > + if (state && output->crc_enabled) { > > + state->n_frame = drm_crtc_accurate_vblank_count(crtc); > > + queue_work(output->crc_workq, &state->crc_work); > > + } > > + > > + spin_unlock(&output->lock); > > +} > > + > > +static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer) > > +{ > > + struct vkms_output *output = container_of(timer, struct vkms_output, > > + vblank_hrtimer); > > + int ret_overrun; > > + > > + _vblank_handle(output); > > + > > ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer, > > output->period_ns); > > > > @@ -97,18 +112,22 @@ vkms_atomic_crtc_duplicate_state(struct drm_crtc *crtc) > > > > __drm_atomic_helper_crtc_duplicate_state(crtc, &vkms_state->base); > > > > + INIT_WORK(&vkms_state->crc_work, vkms_crc_work_handle); > > + > > return &vkms_state->base; > > } > > > > static void vkms_atomic_crtc_destroy_state(struct drm_crtc *crtc, > > struct drm_crtc_state *state) > > { > > - struct vkms_crtc_state *vkms_state; > > - > > - vkms_state = to_vkms_crtc_state(state); > > + struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(state); > > > > __drm_atomic_helper_crtc_destroy_state(state); > > - kfree(vkms_state); > > + > > + if (vkms_state) { > > + flush_work(&vkms_state->crc_work); > > + kfree(vkms_state); > > + } > > } > > > > static const struct drm_crtc_funcs vkms_crtc_funcs = { > > @@ -120,6 +139,7 @@ static const struct drm_crtc_funcs vkms_crtc_funcs = { > > .atomic_destroy_state = vkms_atomic_crtc_destroy_state, > > .enable_vblank = vkms_enable_vblank, > > .disable_vblank = vkms_disable_vblank, > > + .set_crc_source = vkms_set_crc_source, > > }; > > > > static void vkms_crtc_atomic_enable(struct drm_crtc *crtc, > > @@ -134,9 +154,21 @@ static void vkms_crtc_atomic_disable(struct drm_crtc *crtc, > > drm_crtc_vblank_off(crtc); > > } > > > > +static void vkms_crtc_atomic_begin(struct drm_crtc *crtc, > > + struct drm_crtc_state *old_crtc_state) > > +{ > > + struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc); > > + > > + /* This lock is held across the atomic commit to block vblamk timer > > + * from scheduling vkms_crc_work_handle until the crc_data is updated > > + */ > > + spin_lock_irq(&vkms_output->lock); > > +} > > + > > static void vkms_crtc_atomic_flush(struct drm_crtc *crtc, > > struct drm_crtc_state *old_crtc_state) > > { > > + struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc); > > unsigned long flags; > > > > if (crtc->state->event) { > > @@ -151,9 +183,12 @@ static void vkms_crtc_atomic_flush(struct drm_crtc *crtc, > > > > crtc->state->event = NULL; > > } > > + > > + spin_unlock_irq(&vkms_output->lock); > > } > > > > static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = { > > + .atomic_begin = vkms_crtc_atomic_begin, > > .atomic_flush = vkms_crtc_atomic_flush, > > .atomic_enable = vkms_crtc_atomic_enable, > > .atomic_disable = vkms_crtc_atomic_disable, > > @@ -162,6 +197,7 @@ static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = { > > int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc, > > struct drm_plane *primary, struct drm_plane *cursor) > > { > > + struct vkms_output *vkms_out = drm_crtc_to_vkms_output(crtc); > > int ret; > > > > ret = drm_crtc_init_with_planes(dev, crtc, primary, cursor, > > @@ -173,5 +209,9 @@ int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc, > > > > drm_crtc_helper_add(crtc, &vkms_crtc_helper_funcs); > > > > + spin_lock_init(&vkms_out->lock); > > + > > + vkms_out->crc_workq = alloc_ordered_workqueue("vkms_crc_workq", 0); > > + > > return ret; > > } > > diff --git a/drivers/gpu/drm/vkms/vkms_drv.c b/drivers/gpu/drm/vkms/vkms_drv.c > > index e340aa128b61..519a353cd909 100644 > > --- a/drivers/gpu/drm/vkms/vkms_drv.c > > +++ b/drivers/gpu/drm/vkms/vkms_drv.c > > @@ -79,6 +79,7 @@ static void vkms_release(struct drm_device *dev) > > drm_atomic_helper_shutdown(&vkms->drm); > > drm_mode_config_cleanup(&vkms->drm); > > drm_dev_fini(&vkms->drm); > > + destroy_workqueue(vkms->output.crc_workq); > > } > > > > static struct drm_driver vkms_driver = { > > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h > > index a1b206643c10..de1ddf31341b 100644 > > --- a/drivers/gpu/drm/vkms/vkms_drv.h > > +++ b/drivers/gpu/drm/vkms/vkms_drv.h > > @@ -20,20 +20,31 @@ static const u32 vkms_formats[] = { > > DRM_FORMAT_XRGB8888, > > }; > > > > +struct vkms_crc_data { > > + struct drm_rect src; > > + struct drm_framebuffer fb; > > +}; > > + > > /** > > * vkms_plane_state - Driver specific plane state > > * @base: base plane state > > + * @crc_data: data required for CRC computation > > */ > > struct vkms_plane_state { > > struct drm_plane_state base; > > + struct vkms_crc_data *crc_data; > > }; > > > > /** > > * vkms_crtc_state - Driver specific CRTC state > > * @base: base CRTC state > > + * @crc_work: work struct to compute and add CRC entries > > + * @n_frame: frame number for computed CRC > > */ > > struct vkms_crtc_state { > > struct drm_crtc_state base; > > + struct work_struct crc_work; > > + unsigned int n_frame; > > }; > > > > struct vkms_output { > > @@ -43,6 +54,11 @@ struct vkms_output { > > struct hrtimer vblank_hrtimer; > > ktime_t period_ns; > > struct drm_pending_vblank_event *event; > > + bool crc_enabled; > > + /* ordered wq for crc_work */ > > + struct workqueue_struct *crc_workq; > > + /* protects concurrent access to crc_data */ > > + spinlock_t lock; > > }; > > > > struct vkms_device { > > @@ -106,4 +122,9 @@ int vkms_gem_vmap(struct drm_gem_object *obj); > > > > void vkms_gem_vunmap(struct drm_gem_object *obj); > > > > +/* CRC Support */ > > +int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name, > > + size_t *values_cnt); > > +void vkms_crc_work_handle(struct work_struct *work); > > + > > #endif /* _VKMS_DRV_H_ */ > > diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c > > index 70fca22bc51b..c91661631c76 100644 > > --- a/drivers/gpu/drm/vkms/vkms_plane.c > > +++ b/drivers/gpu/drm/vkms/vkms_plane.c > > @@ -16,11 +16,18 @@ static struct drm_plane_state * > > vkms_plane_duplicate_state(struct drm_plane *plane) > > { > > struct vkms_plane_state *vkms_state; > > + struct vkms_crc_data *crc_data; > > > > vkms_state = kzalloc(sizeof(*vkms_state), GFP_KERNEL); > > if (!vkms_state) > > return NULL; > > > > + crc_data = kzalloc(sizeof(*crc_data), GFP_KERNEL); > > + if (WARN_ON(!crc_data)) > > + DRM_INFO("Couldn't allocate crc_data"); > > + > > + vkms_state->crc_data = crc_data; > > + > > __drm_atomic_helper_plane_duplicate_state(plane, > > &vkms_state->base); > > > > @@ -31,6 +38,18 @@ static void vkms_plane_destroy_state(struct drm_plane *plane, > > struct drm_plane_state *old_state) > > { > > struct vkms_plane_state *vkms_state = to_vkms_plane_state(old_state); > > + struct drm_crtc *crtc = vkms_state->base.crtc; > > + > > + if (crtc) { > > + /* dropping the reference we acquired in > > + * vkms_primary_plane_update() > > + */ > > + if (drm_framebuffer_read_refcount(&vkms_state->crc_data->fb)) > > + drm_framebuffer_put(&vkms_state->crc_data->fb); > > + } > > + > > + kfree(vkms_state->crc_data); > > + vkms_state->crc_data = NULL; > > > > __drm_atomic_helper_plane_destroy_state(old_state); > > kfree(vkms_state); > > @@ -65,6 +84,17 @@ static const struct drm_plane_funcs vkms_plane_funcs = { > > static void vkms_primary_plane_update(struct drm_plane *plane, > > struct drm_plane_state *old_state) > > { > > + struct vkms_plane_state *vkms_plane_state; > > + struct vkms_crc_data *crc_data; > > + > > + if (!plane->state->crtc || !plane->state->fb) > > + return; > > + > > + vkms_plane_state = to_vkms_plane_state(plane->state); > > + crc_data = vkms_plane_state->crc_data; > > + memcpy(&crc_data->src, &plane->state->src, sizeof(struct drm_rect)); > > + memcpy(&crc_data->fb, plane->state->fb, sizeof(struct drm_framebuffer)); > > + drm_framebuffer_get(&crc_data->fb); > > } > > > > static int vkms_plane_atomic_check(struct drm_plane *plane, > > -- > > 2.17.1 > > -- Sean Paul, Software Engineer, Google / Chromium OS _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
