[PATCH 2/2] drm/vkms: Compute CRC with Cursor Plane

Haneen Mohammed hamohammed.sa at gmail.com
Wed Aug 15 23:05:14 UTC 2018


On Tue, Aug 14, 2018 at 09:52:33PM +0200, Daniel Vetter wrote:
> On Tue, Aug 14, 2018 at 9:03 PM, Haneen Mohammed
> <hamohammed.sa at gmail.com> wrote:
> > On Tue, Aug 14, 2018 at 10:21:29AM +0200, Daniel Vetter wrote:
> >> On Mon, Aug 13, 2018 at 11:04:11PM +0300, Haneen Mohammed wrote:
> >> > On Wed, Aug 08, 2018 at 10:23:27AM +0200, Daniel Vetter wrote:
> >> > > On Wed, Aug 08, 2018 at 06:53:17AM +0300, Haneen Mohammed wrote:
> >> > > > On Tue, Aug 07, 2018 at 06:33:36PM +0200, Daniel Vetter wrote:
> >> > > > > On Mon, Aug 06, 2018 at 06:58:29AM +0300, Haneen Mohammed wrote:
> >> > > > > > This patch compute CRC for output frame with cursor and primary plane.
> >> > > > > > Blend cursor with primary plane and compute CRC on the resulted frame.
> >> > > > > >
> >> > > > > > Signed-off-by: Haneen Mohammed <hamohammed.sa at gmail.com>
> >> > > > >
> >> > > > > Nice!
> >> > > > >
> >> > > > > I assume with this you're passing all the crc based cursor tests in igt?
> >> > > > > If so, please mention this in the commit message, so that there's a record
> >> > > > > of the testing done on this.
> >> > > > >
> >> > > >
> >> > > > Sure, I'll update the commit message.
> >> > > > Is there any other change I should add/fix to this patchset?
> >> > > >
> >> > > > > One fairly huge gap we iirc have in our cursor testing is that there's not
> >> > > > > much (if any?) alpha blending coverage. We kinda need that to make sure
> >> > > > > this all works correctly. The usual trick is to only check the extreme
> >> > > > > alpha values, i.e. fully opaque and fully transparent, since intermediate
> >> > > > > values are affected by hw-specific rounding modes.
> >> > > > > > ---
> >> > > > > >  drivers/gpu/drm/vkms/vkms_crc.c   | 149 +++++++++++++++++++++++++-----
> >> > > > > >  drivers/gpu/drm/vkms/vkms_drv.h   |   5 +-
> >> > > > > >  drivers/gpu/drm/vkms/vkms_plane.c |  10 +-
> >> > > > > >  3 files changed, 137 insertions(+), 27 deletions(-)
> >> > > > > >
> >> > > > > > diff --git a/drivers/gpu/drm/vkms/vkms_crc.c b/drivers/gpu/drm/vkms/vkms_crc.c
> >> > > > > > index 37d717f38e3c..4853a739ae5a 100644
> >> > > > > > --- a/drivers/gpu/drm/vkms/vkms_crc.c
> >> > > > > > +++ b/drivers/gpu/drm/vkms/vkms_crc.c
> >> > > > > > @@ -1,36 +1,137 @@
> >> > > > > >  // SPDX-License-Identifier: GPL-2.0
> >> > > > > >  #include "vkms_drv.h"
> >> > > > > >  #include <linux/crc32.h>
> >> > > > > > +#include <drm/drm_atomic.h>
> >> > > > > > +#include <drm/drm_atomic_helper.h>
> >> > > > > >  #include <drm/drm_gem_framebuffer_helper.h>
> >> > > > > >
> >> > > > > > -static uint32_t _vkms_get_crc(struct vkms_crc_data *crc_data)
> >> > > > > > +/**
> >> > > > > > + * compute_crc - Compute CRC value on output frame
> >> > > > > > + *
> >> > > > > > + * @vaddr_out: address to final framebuffer
> >> > > > > > + * @crc_out: framebuffer's metadata
> >> > > > > > + *
> >> > > > > > + * returns CRC value computed using crc32 on the visible portion of
> >> > > > > > + * the final framebuffer at vaddr_out
> >> > > > > > + */
> >> > > > > > +static uint32_t compute_crc(void *vaddr_out, struct vkms_crc_data *crc_out)
> >> > > > > >  {
> >> > > > > > -   struct drm_framebuffer *fb = &crc_data->fb;
> >> > > > > > +   int i, src_offset;
> >> > > > > > +   int x_src = crc_out->src.x1 >> 16;
> >> > > > > > +   int y_src = crc_out->src.y1 >> 16;
> >> > > > > > +   int h_src = drm_rect_height(&crc_out->src) >> 16;
> >> > > > > > +   int w_src = drm_rect_width(&crc_out->src) >> 16;
> >> > > > > > +   int size_byte = w_src * crc_out->cpp;
> >> > > > > > +   u32 crc = 0;
> >> > > > > > +
> >> > > > > > +   for (i = y_src; i < y_src + h_src; i++) {
> >> > > > > > +           src_offset = crc_out->offset
> >> > > > > > +                        + (i * crc_out->pitch)
> >> > > > > > +                        + (x_src * crc_out->cpp);
> >> > > > > > +           crc = crc32_le(crc, vaddr_out + src_offset, size_byte);
> >> > > > > > +   }
> >> > > > > > +
> >> > > > > > +   return crc;
> >> > > > > > +}
> >> > > > > > +
> >> >
> >> > Hey Daniel,
> >> >
> >> > When I change the above function "compute_crc" to compute the CRC for
> >> > each pixel so we can clear the Alpha value before computing the CRC as bellow,
> >> > the test "nonblocking-crc-pipe-A-frame-sequence" sometimes failes and
> >> > sometimes passes. Should I still continue with the change, or leave it
> >> > as it is?
> >>
> >> Hm, how does it fail? Could be that the code becomes too slow, and then
> >> the frame counters don't increment nicely anymore. Or there's a race
> >> somewhere in the CRC code that gets exposed. But that's just me guessing.
> >> -Daniel
> >>

Hi Daniel,

I figured out why nonblocking-crc-pipe-A-frame-sequence fails.
queue_work sometimes return false so vkms_crc_work_handle doesn't get scheduled
for a given frame number. I'm not sure though how this can be fixed.

- Haneen

> >
> > Oh sorry I should've elaborated more on how it fails. Yeah I think it
> > becomes too slow and that can cause mismatch to frame counters?
> >
> > -----
> > (kms_pipe_crc_basic:1902) CRITICAL: Failed assertion: crcs[j].frame + 1 == crcs[j + 1].frame
> > (kms_pipe_crc_basic:1902) CRITICAL: Last errno: 9, Bad file descriptor
> > (kms_pipe_crc_basic:1902) CRITICAL: error: 1090928 != 1090929
> > -----
> 
> Yeah misses the deadline it seems.
> 
> > Maybe it's not that bad/slow because I've noticed that this happen
> > occasionally when I enable Ftrace.
> 
> Yeah ftrace can have some decent overhead. And we're adding a pile of
> function calls, because crc32_le isn't inlined. Does it still happen
> without ftrace?
> 
> Optimizing this will be some real work - we'd need a local cache to
> compute an entire block of blended pixels into, then add an entire
> block. Block size needs to be large enough to be efficient, but not so
> big that we start trashing the cache or have to allocate memory (stack
> space in the kernel is very limited). Would be good if we can avoid
> all this work just now ...
> -Danie
> 
> >
> >> >
> >> > ----------------- vkms_crc.c -----------------
> >> >     for (i = y_src; i < y_src + h_src; ++i) {
> >> >             for (j = x_src; j < x_src + w_src; ++j) {
> >> >                     src_offset = crc_out->offset
> >> >                                  + (i * crc_out->pitch)
> >> >                                  + (j * crc_out->cpp);
> >> >                     memset(vaddr_out + src_offset + 24, 0,  8);
> >> >                     crc = crc32_le(crc, vaddr_out + src_offset, sizeof(u32));
> >> >             }
> >> >     }
> >> > ----------------- vkms_crc.c -----------------
> >> >
> >> > Thank you,
> >> > Haneen
> >> >
> >> > > > > > +/**
> >> > > > > > + * blend - belnd value at vaddr_src with value at vaddr_dst
> >> > > > > > + * @vaddr_dst: destination address
> >> > > > > > + * @vaddr_src: source address
> >> > > > > > + * @crc_dst: destination framebuffer's metadata
> >> > > > > > + * @crc_src: source framebuffer's metadata
> >> > > > > > + *
> >> > > > > > + * Blend value at vaddr_src with value at vaddr_dst.
> >> > > > > > + * Currently, this function write value at vaddr_src on value
> >> > > > > > + * at vaddr_dst using buffer's metadata to locate the new values
> >> > > > > > + * from vaddr_src and their distenation at vaddr_dst.
> >> > > > > > + *
> >> > > > > > + * Todo: Use the alpha value to blend vaddr_src with vaddr_dst
> >> > > > > > + *  instead of overwriting it.
> >> > > > >
> >> > > > > Another todo: We must clear the alpha channel in the result after
> >> > > > > blending. This also applies to the primary plane, where the XRGB for the
> >> > > > > pixel format mandates that we entirely ignore the alpha channel.
> >> > > > >
> >> > > > > This is also something we should probably have an igt testcase for.
> >> > > > >
> >> > > > > Since there's a few open ends: How many weeks are left in your outreachy
> >> > > > > internship? We need to make sure that at least all the issues are covered
> >> > > > > in a vkms todo file. Would be great to add that in
> >> > > > > Documentation/gpu/vkms.rst, like we have for other drivers.
> >> > > > > -Daniel
> >> > > > >
> >> > > >
> >> > > > I've one more week! I can use this week to prepare the todo file and
> >> > > > finalize this patch?
> >> > >
> >> > > Yeah sounds like the perfect wrap-up work. Since this wont be enough to
> >> > > finish the cursor work it would be good to hide the cursor setup behind a
> >> > > module option, perhaps "enable_cursor" or so. That way we wont have
> >> > > not-totally-correct features enabled. And enabling/disabling cursor
> >> > > support could be useful for testing.
> >> > > -Daniel
> >> > >
> >> > > >
> >> > > > Thank you,
> >> > > > Haneen
> >> > > >
> >> > > > > > + */
> >> > > > > > +static void blend(void *vaddr_dst, void *vaddr_src,
> >> > > > > > +             struct vkms_crc_data *crc_dst,
> >> > > > > > +             struct vkms_crc_data *crc_src)
> >> > > > > > +{
> >> > > > > > +   int i, j, j_dst, i_dst;
> >> > > > > > +   int offset_src, offset_dst;
> >> > > > > > +
> >> > > > > > +   int x_src = crc_src->src.x1 >> 16;
> >> > > > > > +   int y_src = crc_src->src.y1 >> 16;
> >> > > > > > +
> >> > > > > > +   int x_dst = crc_src->dst.x1;
> >> > > > > > +   int y_dst = crc_src->dst.y1;
> >> > > > > > +   int h_dst = drm_rect_height(&crc_src->dst);
> >> > > > > > +   int w_dst = drm_rect_width(&crc_src->dst);
> >> > > > > > +
> >> > > > > > +   int y_limit = y_src + h_dst;
> >> > > > > > +   int x_limit = x_src + w_dst;
> >> > > > > > +
> >> > > > > > +   for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
> >> > > > > > +           for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
> >> > > > > > +                   offset_dst = crc_dst->offset
> >> > > > > > +                                + (i_dst * crc_dst->pitch)
> >> > > > > > +                                + (j_dst++ * crc_dst->cpp);
> >> > > > > > +                   offset_src = crc_src->offset
> >> > > > > > +                                + (i * crc_src->pitch)
> >> > > > > > +                                + (j * crc_src->cpp);
> >> > > > > > +
> >> > > > > > +                   memcpy(vaddr_dst + offset_dst,
> >> > > > > > +                          vaddr_src + offset_src, sizeof(u32));
> >> > > > > > +           }
> >> > > > > > +           i_dst++;
> >> > > > > > +   }
> >> > > > > > +}
> >> > > > > > +
> >> > > > > > +static void compose_cursor(struct vkms_crc_data *cursor_crc,
> >> > > > > > +                      struct vkms_crc_data *primary_crc, void *vaddr_out)
> >> > > > > > +{
> >> > > > > > +   struct drm_gem_object *cursor_obj;
> >> > > > > > +   struct vkms_gem_object *cursor_vkms_obj;
> >> > > > > > +
> >> > > > > > +   cursor_obj = drm_gem_fb_get_obj(&cursor_crc->fb, 0);
> >> > > > > > +   cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);
> >> > > > > > +
> >> > > > > > +   mutex_lock(&cursor_vkms_obj->pages_lock);
> >> > > > > > +   if (WARN_ON(!cursor_vkms_obj->vaddr))
> >> > > > > > +           goto out;
> >> > > > > > +
> >> > > > > > +   blend(vaddr_out, cursor_vkms_obj->vaddr, primary_crc, cursor_crc);
> >> > > > > > +
> >> > > > > > +out:
> >> > > > > > +   mutex_unlock(&cursor_vkms_obj->pages_lock);
> >> > > > > > +}
> >> > > > > > +
> >> > > > > > +static uint32_t _vkms_get_crc(struct vkms_crc_data *primary_crc,
> >> > > > > > +                         struct vkms_crc_data *cursor_crc)
> >> > > > > > +{
> >> > > > > > +   struct drm_framebuffer *fb = &primary_crc->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);
> >> > > > > > +   void *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
> >> > > > > >     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))
> >> > > > > > -           goto out;
> >> > > > > > +   if (!vaddr_out) {
> >> > > > > > +           DRM_ERROR("Failed to allocate memory for output frame.");
> >> > > > > > +           return 0;
> >> > > > > > +   }
> >> > > > > >
> >> > > > > > -   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_lock(&vkms_obj->pages_lock);
> >> > > > > > +   if (WARN_ON(!vkms_obj->vaddr)) {
> >> > > > > > +           mutex_lock(&vkms_obj->pages_lock);
> >> > > > > > +           return crc;
> >> > > > > >     }
> >> > > > > >
> >> > > > > > -out:
> >> > > > > > +   memcpy(vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
> >> > > > > >     mutex_unlock(&vkms_obj->pages_lock);
> >> > > > > > +
> >> > > > > > +   if (cursor_crc)
> >> > > > > > +           compose_cursor(cursor_crc, primary_crc, vaddr_out);
> >> > > > > > +
> >> > > > > > +   crc = compute_crc(vaddr_out, primary_crc);
> >> > > > > > +
> >> > > > > > +   kfree(vaddr_out);
> >> > > > > > +
> >> > > > > >     return crc;
> >> > > > > >  }
> >> > > > > >
> >> > > > > > @@ -44,8 +145,8 @@ void vkms_crc_work_handle(struct work_struct *work)
> >> > > > > >     struct vkms_device *vdev = container_of(out, struct vkms_device,
> >> > > > > >                                             output);
> >> > > > > >     struct vkms_crc_data *primary_crc = NULL;
> >> > > > > > +   struct vkms_crc_data *cursor_crc = NULL;
> >> > > > > >     struct drm_plane *plane;
> >> > > > > > -
> >> > > > > >     u32 crc32 = 0;
> >> > > > > >
> >> > > > > >     drm_for_each_plane(plane, &vdev->drm) {
> >> > > > > > @@ -58,14 +159,14 @@ void vkms_crc_work_handle(struct work_struct *work)
> >> > > > > >             if (drm_framebuffer_read_refcount(&crc_data->fb) == 0)
> >> > > > > >                     continue;
> >> > > > > >
> >> > > > > > -           if (plane->type == DRM_PLANE_TYPE_PRIMARY) {
> >> > > > > > +           if (plane->type == DRM_PLANE_TYPE_PRIMARY)
> >> > > > > >                     primary_crc = crc_data;
> >> > > > > > -                   break;
> >> > > > > > -           }
> >> > > > > > +           else
> >> > > > > > +                   cursor_crc = crc_data;
> >> > > > > >     }
> >> > > > > >
> >> > > > > >     if (primary_crc)
> >> > > > > > -           crc32 = _vkms_get_crc(primary_crc);
> >> > > > > > +           crc32 = _vkms_get_crc(primary_crc, cursor_crc);
> >> > > > > >
> >> > > > > >     drm_crtc_add_crc_entry(crtc, true, crtc_state->n_frame, &crc32);
> >> > > > > >  }
> >> > > > > > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h
> >> > > > > > index 36e524f791fe..173875dc361e 100644
> >> > > > > > --- a/drivers/gpu/drm/vkms/vkms_drv.h
> >> > > > > > +++ b/drivers/gpu/drm/vkms/vkms_drv.h
> >> > > > > > @@ -25,8 +25,11 @@ static const u32 vkms_cursor_formats[] = {
> >> > > > > >  };
> >> > > > > >
> >> > > > > >  struct vkms_crc_data {
> >> > > > > > -   struct drm_rect src;
> >> > > > > >     struct drm_framebuffer fb;
> >> > > > > > +   struct drm_rect src, dst;
> >> > > > > > +   unsigned int offset;
> >> > > > > > +   unsigned int pitch;
> >> > > > > > +   unsigned int cpp;
> >> > > > > >  };
> >> > > > > >
> >> > > > > >  /**
> >> > > > > > diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
> >> > > > > > index 428247d403dc..7041007396ae 100644
> >> > > > > > --- a/drivers/gpu/drm/vkms/vkms_plane.c
> >> > > > > > +++ b/drivers/gpu/drm/vkms/vkms_plane.c
> >> > > > > > @@ -85,16 +85,22 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
> >> > > > > >                                  struct drm_plane_state *old_state)
> >> > > > > >  {
> >> > > > > >     struct vkms_plane_state *vkms_plane_state;
> >> > > > > > +   struct drm_framebuffer *fb = plane->state->fb;
> >> > > > > >     struct vkms_crc_data *crc_data;
> >> > > > > >
> >> > > > > > -   if (!plane->state->crtc || !plane->state->fb)
> >> > > > > > +   if (!plane->state->crtc || !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));
> >> > > > > > +   memcpy(&crc_data->dst, &plane->state->dst, sizeof(struct drm_rect));
> >> > > > > > +   memcpy(&crc_data->fb, fb, sizeof(struct drm_framebuffer));
> >> > > > > >     drm_framebuffer_get(&crc_data->fb);
> >> > > > > > +   crc_data->offset = fb->offsets[0];
> >> > > > > > +   crc_data->pitch = fb->pitches[0];
> >> > > > > > +   crc_data->cpp = fb->format->cpp[0];
> >> > > > > >  }
> >> > > > > >
> >> > > > > >  static int vkms_plane_atomic_check(struct drm_plane *plane,
> >> > > > > > --
> >> > > > > > 2.17.1
> >> > > > > >
> >> > > > >
> >> > > > > --
> >> > > > > Daniel Vetter
> >> > > > > Software Engineer, Intel Corporation
> >> > > > > http://blog.ffwll.ch
> >> > >
> >> > > --
> >> > > Daniel Vetter
> >> > > Software Engineer, Intel Corporation
> >> > > http://blog.ffwll.ch
> >>
> >> --
> >> Daniel Vetter
> >> Software Engineer, Intel Corporation
> >> http://blog.ffwll.ch
> 
> 
> 
> -- 
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch


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