modesetting: Use GAMMA_LUT when available

If the kernel exposes GAMMA_LUT and GAMMA_LUT_SIZE properties and the size is
not what the server has pre-configured for the crtc, free the old gamma ramp
memory allocated by the server and replace it with new allocations of the
appropriate size.

In addition, when GAMMA_LUT is available, use drmModeCreatePropertyBlob() and
drmModeObjectSetProperty() to set the gamma ramp rather than using the legacy
drmModeCrtcSetGamma() function.

Add a new option "UseGammaLUT" to allow disabling this new behavior and falling
back to drmModeCrtcSetGamma() unconditionally.

Signed-off-by: Aaron Plattner <aplattner@nvidia.com>
This commit is contained in:
Aaron Plattner 2019-10-24 13:46:35 -07:00
parent b6985d6b3f
commit 245b9db03a
5 changed files with 81 additions and 2 deletions

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@ -140,6 +140,7 @@ static const OptionInfoRec Options[] = {
{OPTION_DOUBLE_SHADOW, "DoubleShadow", OPTV_BOOLEAN, {0}, FALSE},
{OPTION_ATOMIC, "Atomic", OPTV_BOOLEAN, {0}, FALSE},
{OPTION_VARIABLE_REFRESH, "VariableRefresh", OPTV_BOOLEAN, {0}, FALSE},
{OPTION_USE_GAMMA_LUT, "UseGammaLUT", OPTV_BOOLEAN, {0}, FALSE},
{-1, NULL, OPTV_NONE, {0}, FALSE}
};

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@ -57,6 +57,7 @@ typedef enum {
OPTION_DOUBLE_SHADOW,
OPTION_ATOMIC,
OPTION_VARIABLE_REFRESH,
OPTION_USE_GAMMA_LUT,
} modesettingOpts;
typedef struct

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@ -1669,6 +1669,35 @@ drmmode_show_cursor(xf86CrtcPtr crtc)
return drmmode_set_cursor(crtc);
}
static void
drmmode_set_gamma_lut(drmmode_crtc_private_ptr drmmode_crtc,
uint16_t * red, uint16_t * green, uint16_t * blue,
int size)
{
drmmode_ptr drmmode = drmmode_crtc->drmmode;
drmmode_prop_info_ptr gamma_lut_info =
&drmmode_crtc->props[DRMMODE_CRTC_GAMMA_LUT];
const uint32_t crtc_id = drmmode_crtc->mode_crtc->crtc_id;
uint32_t blob_id;
struct drm_color_lut lut[size];
assert(gamma_lut_info->prop_id != 0);
for (int i = 0; i < size; i++) {
lut[i].red = red[i];
lut[i].green = green[i];
lut[i].blue = blue[i];
}
if (drmModeCreatePropertyBlob(drmmode->fd, lut, sizeof(lut), &blob_id))
return;
drmModeObjectSetProperty(drmmode->fd, crtc_id, DRM_MODE_OBJECT_CRTC,
gamma_lut_info->prop_id, blob_id);
drmModeDestroyPropertyBlob(drmmode->fd, blob_id);
}
static void
drmmode_crtc_gamma_set(xf86CrtcPtr crtc, uint16_t * red, uint16_t * green,
uint16_t * blue, int size)
@ -1676,8 +1705,12 @@ drmmode_crtc_gamma_set(xf86CrtcPtr crtc, uint16_t * red, uint16_t * green,
drmmode_crtc_private_ptr drmmode_crtc = crtc->driver_private;
drmmode_ptr drmmode = drmmode_crtc->drmmode;
drmModeCrtcSetGamma(drmmode->fd, drmmode_crtc->mode_crtc->crtc_id,
size, red, green, blue);
if (drmmode_crtc->use_gamma_lut) {
drmmode_set_gamma_lut(drmmode_crtc, red, green, blue, size);
} else {
drmModeCrtcSetGamma(drmmode->fd, drmmode_crtc->mode_crtc->crtc_id,
size, red, green, blue);
}
}
static Bool
@ -2266,6 +2299,8 @@ drmmode_crtc_init(ScrnInfoPtr pScrn, drmmode_ptr drmmode, drmModeResPtr mode_res
static const drmmode_prop_info_rec crtc_props[] = {
[DRMMODE_CRTC_ACTIVE] = { .name = "ACTIVE" },
[DRMMODE_CRTC_MODE_ID] = { .name = "MODE_ID" },
[DRMMODE_CRTC_GAMMA_LUT] = { .name = "GAMMA_LUT" },
[DRMMODE_CRTC_GAMMA_LUT_SIZE] = { .name = "GAMMA_LUT_SIZE" },
};
crtc = xf86CrtcCreate(pScrn, &drmmode_crtc_funcs);
@ -2302,6 +2337,39 @@ drmmode_crtc_init(ScrnInfoPtr pScrn, drmmode_ptr drmmode, drmModeResPtr mode_res
xf86DrvMsgVerb(pScrn->scrnIndex, X_INFO, MS_LOGLEVEL_DEBUG,
"Allocated crtc nr. %d to this screen.\n", num);
/* If the GAMMA_LUT property is available, replace the server's default
* gamma ramps with ones of the appropriate size. */
if (drmmode_crtc->props[DRMMODE_CRTC_GAMMA_LUT_SIZE].prop_id) {
Bool try_gamma_lut =
xf86ReturnOptValBool(drmmode->Options, OPTION_USE_GAMMA_LUT, TRUE);
uint64_t size = drmmode_crtc->props[DRMMODE_CRTC_GAMMA_LUT_SIZE].value;
if (try_gamma_lut && size != crtc->gamma_size) {
uint16_t *gamma = malloc(3 * size * sizeof(uint16_t));
if (gamma) {
free(crtc->gamma_red);
crtc->gamma_size = size;
crtc->gamma_red = gamma;
crtc->gamma_green = gamma + size;
crtc->gamma_blue = gamma + size * 2;
drmmode_crtc->use_gamma_lut = TRUE;
xf86DrvMsgVerb(pScrn->scrnIndex, X_INFO, MS_LOGLEVEL_DEBUG,
"Gamma ramp set to %ld entries on CRTC %d\n",
size, num);
} else {
xf86DrvMsg(pScrn->scrnIndex, X_WARNING,
"Failed to allocate memory for %ld gamma ramp "
"entries on CRTC %d. Falling back to legacy "
"%d-entry mode.\n",
size, num, crtc->gamma_size);
}
}
}
return 1;
}

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@ -67,6 +67,8 @@ enum drmmode_connector_property {
enum drmmode_crtc_property {
DRMMODE_CRTC_ACTIVE,
DRMMODE_CRTC_MODE_ID,
DRMMODE_CRTC_GAMMA_LUT,
DRMMODE_CRTC_GAMMA_LUT_SIZE,
DRMMODE_CRTC__COUNT
};
@ -199,6 +201,7 @@ typedef struct {
Bool flipping_active;
Bool vrr_enabled;
Bool use_gamma_lut;
} drmmode_crtc_private_rec, *drmmode_crtc_private_ptr;
typedef struct {

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@ -81,6 +81,12 @@ For example:
Option \*qZaphodHeads\*q \*qLVDS,VGA-0\*q
will assign xrandr outputs LVDS and VGA-0 to this instance of the driver.
.TP
.BI "Option \*qUseGammaLUT\*q \*q" boolean \*q
Enable or disable use of the GAMMA_LUT property, when available.
When enabled, this option allows the driver to use gamma ramps with more
entries, if supported by the kernel.
Default: on.
.TP
.SH "SEE ALSO"
@xservername@(@appmansuffix@), @xconfigfile@(@filemansuffix@), Xserver(@appmansuffix@),
X(@miscmansuffix@)