diff options
| author |   Mikulas Patocka <mpatocka@redhat.com> | 2018-06-03 16:41:00 +0200 |
|---|---|---|
| committer |   Dave Airlie <airlied@redhat.com> | 2018-07-31 08:11:12 +1000 |
| commit | 91ba11fb7d7ca0a3bbe8a512e65e666e2ec1e889 (patch) | |
| tree | 65aca2b7e173c4cdc0658b2feb826b07277f8f50 /drivers/gpu/drm/udl/udl_fb.c | |
| parent | udl-kms: fix crash due to uninitialized memory (diff) | |
| download | linux-dev-91ba11fb7d7ca0a3bbe8a512e65e666e2ec1e889.tar.xz linux-dev-91ba11fb7d7ca0a3bbe8a512e65e666e2ec1e889.zip | |
udl-kms: avoid division
Division is slow, so it shouldn't be done by the pixel generating code.
The driver supports only 2 or 4 bytes per pixel, so we can replace
division with a shift.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'drivers/gpu/drm/udl/udl_fb.c')
| -rw-r--r-- | drivers/gpu/drm/udl/udl_fb.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/drivers/gpu/drm/udl/udl_fb.c b/drivers/gpu/drm/udl/udl_fb.c index c3f5867dac91..8746eeeec44d 100644 --- a/drivers/gpu/drm/udl/udl_fb.c +++ b/drivers/gpu/drm/udl/udl_fb.c @@ -90,7 +90,10 @@ int udl_handle_damage(struct udl_framebuffer *fb, int x, int y, int bytes_identical = 0; struct urb *urb; int aligned_x; - int bpp = fb->base.format->cpp[0]; + int log_bpp; + + BUG_ON(!is_power_of_2(fb->base.format->cpp[0])); + log_bpp = __ffs(fb->base.format->cpp[0]); if (!fb->active_16) return 0; @@ -125,12 +128,12 @@ int udl_handle_damage(struct udl_framebuffer *fb, int x, int y, for (i = y; i < y + height ; i++) { const int line_offset = fb->base.pitches[0] * i; - const int byte_offset = line_offset + (x * bpp); - const int dev_byte_offset = (fb->base.width * bpp * i) + (x * bpp); - if (udl_render_hline(dev, bpp, &urb, + const int byte_offset = line_offset + (x << log_bpp); + const int dev_byte_offset = (fb->base.width * i + x) << log_bpp; + if (udl_render_hline(dev, log_bpp, &urb, (char *) fb->obj->vmapping, &cmd, byte_offset, dev_byte_offset, - width * bpp, + width << log_bpp, &bytes_identical, &bytes_sent)) goto error; } @@ -149,7 +152,7 @@ int udl_handle_damage(struct udl_framebuffer *fb, int x, int y, error: atomic_add(bytes_sent, &udl->bytes_sent); atomic_add(bytes_identical, &udl->bytes_identical); - atomic_add(width*height*bpp, &udl->bytes_rendered); + atomic_add((width * height) << log_bpp, &udl->bytes_rendered); end_cycles = get_cycles(); atomic_add(((unsigned int) ((end_cycles - start_cycles) >> 10)), /* Kcycles */ |