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| author | Paul Cercueil <paul@crapouillou.net> | 2020-11-05 08:39:05 +0000 |
|---|---|---|
| committer | Paul Cercueil <paul@crapouillou.net> | 2020-11-11 11:47:11 +0000 |
| commit | abec017c3d1f47edf7d1e48a2ed45f0e69413a80 (patch) | |
| tree | 446de3ca2d85e08c997f308be359b5827ebb4dc3 /drivers/gpu/drm/ingenic | |
| parent | 28a68f828266754c2bd64b87873e8099e3f8fe0c (diff) | |
| download | linux-abec017c3d1f47edf7d1e48a2ed45f0e69413a80.tar.bz2 | |
drm/ingenic: ipu: Search for scaling coefs up to 102% of the screen
Increase the scaled image's theorical width/height until we find a
configuration that has valid scaling coefficients, up to 102% of the
screen's resolution. This makes sure that we can scale from almost
every resolution possible at the cost of a very small distorsion.
The CRTC_W / CRTC_H are not modified.
This algorithm was already in place but would not try to go above the
screen's resolution, and as a result would only work if the CRTC_W /
CRTC_H were smaller than the screen resolution. It will now try until it
reaches 102% of the screen's resolution.
Note that this algorithm exists mostly as a band-aid for a missing
functionality: it is not possible for userspace to request the closest
mode that would encapsulate the provided one, because the GEM buffer is
created beforehand. If there was a way to let the kernel tweak the mode,
I could write a better algorithm that would result in a better looking
picture.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201105083905.8780-1-paul@crapouillou.net
Diffstat (limited to 'drivers/gpu/drm/ingenic')
| -rw-r--r-- | drivers/gpu/drm/ingenic/ingenic-ipu.c | 23 |
1 files changed, 15 insertions, 8 deletions
diff --git a/drivers/gpu/drm/ingenic/ingenic-ipu.c b/drivers/gpu/drm/ingenic/ingenic-ipu.c index fc8c6e970ee3..e52777ef85fd 100644 --- a/drivers/gpu/drm/ingenic/ingenic-ipu.c +++ b/drivers/gpu/drm/ingenic/ingenic-ipu.c @@ -516,7 +516,7 @@ static void ingenic_ipu_plane_atomic_update(struct drm_plane *plane, static int ingenic_ipu_plane_atomic_check(struct drm_plane *plane, struct drm_plane_state *state) { - unsigned int num_w, denom_w, num_h, denom_h, xres, yres; + unsigned int num_w, denom_w, num_h, denom_h, xres, yres, max_w, max_h; struct ingenic_ipu *ipu = plane_to_ingenic_ipu(plane); struct drm_crtc *crtc = state->crtc ?: plane->state->crtc; struct drm_crtc_state *crtc_state; @@ -558,19 +558,26 @@ static int ingenic_ipu_plane_atomic_check(struct drm_plane *plane, xres = state->src_w >> 16; yres = state->src_h >> 16; - /* Adjust the coefficients until we find a valid configuration */ - for (denom_w = xres, num_w = state->crtc_w; - num_w <= crtc_state->mode.hdisplay; num_w++) + /* + * Increase the scaled image's theorical width/height until we find a + * configuration that has valid scaling coefficients, up to 102% of the + * screen's resolution. This makes sure that we can scale from almost + * every resolution possible at the cost of a very small distorsion. + * The CRTC_W / CRTC_H are not modified. + */ + max_w = crtc_state->mode.hdisplay * 102 / 100; + max_h = crtc_state->mode.vdisplay * 102 / 100; + + for (denom_w = xres, num_w = state->crtc_w; num_w <= max_w; num_w++) if (!reduce_fraction(&num_w, &denom_w)) break; - if (num_w > crtc_state->mode.hdisplay) + if (num_w > max_w) return -EINVAL; - for (denom_h = yres, num_h = state->crtc_h; - num_h <= crtc_state->mode.vdisplay; num_h++) + for (denom_h = yres, num_h = state->crtc_h; num_h <= max_h; num_h++) if (!reduce_fraction(&num_h, &denom_h)) break; - if (num_h > crtc_state->mode.vdisplay) + if (num_h > max_h) return -EINVAL; ipu->num_w = num_w; |