xfree86/modes: Adapt xf86Randr12CrtcComputeGamma() for depth 30. (v2)

At screen depths > 24 bit, the color palettes passed into
xf86Randr12CrtcComputeGamma() can have a larger number of slots
than the crtc's hardware lut. E.g., at depth 30, 1024 palette
slots vs. 256 hw lut slots. This palette size > crtc gamma size
case is not handled yet and leads to silent failure, so gamma
table updates do not happen.

Add a new subsampling path for this case.

This makes lut updates work again, as tested with the xgamma
utility (uses XF86VidMode extension) and some RandR based
gamma ramp animation.

v2: Better resampling when subsampling the palette, as
    proposed by Ville. Now reaches the max index of the
    palette and deals with non-power-of-two sizes. Thanks.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Reviewed-by: Antoine Martin <antoine@nagafix.co.uk> (v1)
Cc: <ville.syrjala@linux.intel.com>
This commit is contained in:
Mario Kleiner 2018-02-27 03:05:30 +01:00 committed by Adam Jackson
parent 125201408d
commit b5f9fcd50a

View File

@ -1258,40 +1258,82 @@ xf86RandR12CrtcComputeGamma(xf86CrtcPtr crtc, LOCO *palette,
for (shift = 0; (gamma_size << shift) < (1 << 16); shift++);
gamma_slots = crtc->gamma_size / palette_red_size;
for (i = 0; i < palette_red_size; i++) {
value = palette[i].red;
if (gamma_red)
value = gamma_red[value];
else
value <<= shift;
if (crtc->gamma_size >= palette_red_size) {
/* Upsampling of smaller palette to larger hw lut size */
gamma_slots = crtc->gamma_size / palette_red_size;
for (i = 0; i < palette_red_size; i++) {
value = palette[i].red;
if (gamma_red)
value = gamma_red[value];
else
value <<= shift;
for (j = 0; j < gamma_slots; j++)
crtc->gamma_red[i * gamma_slots + j] = value;
for (j = 0; j < gamma_slots; j++)
crtc->gamma_red[i * gamma_slots + j] = value;
}
} else {
/* Downsampling of larger palette to smaller hw lut size */
for (i = 0; i < crtc->gamma_size; i++) {
value = palette[i * (palette_red_size - 1) / (crtc->gamma_size - 1)].red;
if (gamma_red)
value = gamma_red[value];
else
value <<= shift;
crtc->gamma_red[i] = value;
}
}
gamma_slots = crtc->gamma_size / palette_green_size;
for (i = 0; i < palette_green_size; i++) {
value = palette[i].green;
if (gamma_green)
value = gamma_green[value];
else
value <<= shift;
if (crtc->gamma_size >= palette_green_size) {
/* Upsampling of smaller palette to larger hw lut size */
gamma_slots = crtc->gamma_size / palette_green_size;
for (i = 0; i < palette_green_size; i++) {
value = palette[i].green;
if (gamma_green)
value = gamma_green[value];
else
value <<= shift;
for (j = 0; j < gamma_slots; j++)
crtc->gamma_green[i * gamma_slots + j] = value;
for (j = 0; j < gamma_slots; j++)
crtc->gamma_green[i * gamma_slots + j] = value;
}
} else {
/* Downsampling of larger palette to smaller hw lut size */
for (i = 0; i < crtc->gamma_size; i++) {
value = palette[i * (palette_green_size - 1) / (crtc->gamma_size - 1)].green;
if (gamma_green)
value = gamma_green[value];
else
value <<= shift;
crtc->gamma_green[i] = value;
}
}
gamma_slots = crtc->gamma_size / palette_blue_size;
for (i = 0; i < palette_blue_size; i++) {
value = palette[i].blue;
if (gamma_blue)
value = gamma_blue[value];
else
value <<= shift;
if (crtc->gamma_size >= palette_blue_size) {
/* Upsampling of smaller palette to larger hw lut size */
gamma_slots = crtc->gamma_size / palette_blue_size;
for (i = 0; i < palette_blue_size; i++) {
value = palette[i].blue;
if (gamma_blue)
value = gamma_blue[value];
else
value <<= shift;
for (j = 0; j < gamma_slots; j++)
crtc->gamma_blue[i * gamma_slots + j] = value;
for (j = 0; j < gamma_slots; j++)
crtc->gamma_blue[i * gamma_slots + j] = value;
}
} else {
/* Downsampling of larger palette to smaller hw lut size */
for (i = 0; i < crtc->gamma_size; i++) {
value = palette[i * (palette_blue_size - 1) / (crtc->gamma_size - 1)].blue;
if (gamma_blue)
value = gamma_blue[value];
else
value <<= shift;
crtc->gamma_blue[i] = value;
}
}
}