[PATCH v2 5/5] drm/vesadrm: Use helpers for programming gamma ramps
Thomas Zimmermann
tzimmermann at suse.de
Tue May 20 09:40:07 UTC 2025
Replace vesadrm's code for programming the hardware gamma LUT with
DRM helpers. Either load a provided gamma ramp or program a default.
Set the individual entries with a callback.
Each gamma value is given as 3 individual 16-bit values for red,
green and blue. The driver reduces them to 8 bit to make them fit
into hardware registers.
Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
Reviewed-by: Javier Martinez Canillas <javierm at redhat.com>
---
drivers/gpu/drm/sysfb/vesadrm.c | 100 ++++++++++++--------------------
1 file changed, 36 insertions(+), 64 deletions(-)
diff --git a/drivers/gpu/drm/sysfb/vesadrm.c b/drivers/gpu/drm/sysfb/vesadrm.c
index 4d62c78e7d1e..7945544ba73e 100644
--- a/drivers/gpu/drm/sysfb/vesadrm.c
+++ b/drivers/gpu/drm/sysfb/vesadrm.c
@@ -9,6 +9,7 @@
#include <drm/clients/drm_client_setup.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_state_helper.h>
+#include <drm/drm_color_mgmt.h>
#include <drm/drm_connector.h>
#include <drm/drm_damage_helper.h>
#include <drm/drm_device.h>
@@ -87,15 +88,10 @@ static struct vesadrm_device *to_vesadrm_device(struct drm_device *dev)
static void vesadrm_vga_cmap_write(struct vesadrm_device *vesa, unsigned int index,
u16 red, u16 green, u16 blue)
{
- u8 i8, r8, g8, b8;
-
- if (index > 255)
- return;
-
- i8 = index;
- r8 = red >> 8;
- g8 = green >> 8;
- b8 = blue >> 8;
+ u8 i8 = index;
+ u8 r8 = red >> 8;
+ u8 g8 = green >> 8;
+ u8 b8 = blue >> 8;
outb_p(i8, VGA_PEL_IW);
outb_p(r8, VGA_PEL_D);
@@ -120,9 +116,6 @@ static void vesadrm_pmi_cmap_write(struct vesadrm_device *vesa, unsigned int ind
0x00,
};
- if (index > 255)
- return;
-
__asm__ __volatile__ (
"call *(%%esi)"
: /* no return value */
@@ -135,43 +128,36 @@ static void vesadrm_pmi_cmap_write(struct vesadrm_device *vesa, unsigned int ind
}
#endif
-static void vesadrm_set_gamma_linear(struct vesadrm_device *vesa,
- const struct drm_format_info *format)
+static void vesadrm_set_gamma_lut(struct drm_crtc *crtc, unsigned int index,
+ u16 red, u16 green, u16 blue)
+{
+ struct drm_device *dev = crtc->dev;
+ struct vesadrm_device *vesa = to_vesadrm_device(dev);
+ u8 i8 = index & 0xff;
+
+ if (drm_WARN_ON_ONCE(dev, index != i8))
+ return; /* driver bug */
+
+ vesa->cmap_write(vesa, i8, red, green, blue);
+}
+
+static void vesadrm_fill_gamma_lut(struct vesadrm_device *vesa,
+ const struct drm_format_info *format)
{
struct drm_device *dev = &vesa->sysfb.dev;
- size_t i;
- u16 r16, g16, b16;
+ struct drm_crtc *crtc = &vesa->crtc;
switch (format->format) {
case DRM_FORMAT_XRGB1555:
- for (i = 0; i < 32; ++i) {
- r16 = i * 8 + i / 4;
- r16 |= (r16 << 8) | r16;
- vesa->cmap_write(vesa, i, r16, r16, r16);
- }
+ drm_crtc_fill_gamma_555(crtc, vesadrm_set_gamma_lut);
break;
case DRM_FORMAT_RGB565:
- for (i = 0; i < 32; ++i) {
- r16 = i * 8 + i / 4;
- r16 |= (r16 << 8) | r16;
- g16 = i * 4 + i / 16;
- g16 |= (g16 << 8) | g16;
- b16 = r16;
- vesa->cmap_write(vesa, i, r16, g16, b16);
- }
- for (i = 32; i < 64; ++i) {
- g16 = i * 4 + i / 16;
- g16 |= (g16 << 8) | g16;
- vesa->cmap_write(vesa, i, 0, g16, 0);
- }
+ drm_crtc_fill_gamma_565(crtc, vesadrm_set_gamma_lut);
break;
case DRM_FORMAT_RGB888:
case DRM_FORMAT_XRGB8888:
case DRM_FORMAT_BGRX8888:
- for (i = 0; i < 256; ++i) {
- r16 = (i << 8) | i;
- vesa->cmap_write(vesa, i, r16, r16, r16);
- }
+ drm_crtc_fill_gamma_888(crtc, vesadrm_set_gamma_lut);
break;
default:
drm_warn_once(dev, "Unsupported format %p4cc for gamma correction\n",
@@ -180,38 +166,24 @@ static void vesadrm_set_gamma_linear(struct vesadrm_device *vesa,
}
}
-static void vesadrm_set_gamma_lut(struct vesadrm_device *vesa,
- const struct drm_format_info *format,
- struct drm_color_lut *lut)
+static void vesadrm_load_gamma_lut(struct vesadrm_device *vesa,
+ const struct drm_format_info *format,
+ struct drm_color_lut *lut)
{
struct drm_device *dev = &vesa->sysfb.dev;
- size_t i;
- u16 r16, g16, b16;
+ struct drm_crtc *crtc = &vesa->crtc;
switch (format->format) {
case DRM_FORMAT_XRGB1555:
- for (i = 0; i < 32; ++i) {
- r16 = lut[i * 8 + i / 4].red;
- g16 = lut[i * 8 + i / 4].green;
- b16 = lut[i * 8 + i / 4].blue;
- vesa->cmap_write(vesa, i, r16, g16, b16);
- }
+ drm_crtc_load_gamma_555_from_888(crtc, lut, vesadrm_set_gamma_lut);
break;
case DRM_FORMAT_RGB565:
- for (i = 0; i < 32; ++i) {
- r16 = lut[i * 8 + i / 4].red;
- g16 = lut[i * 4 + i / 16].green;
- b16 = lut[i * 8 + i / 4].blue;
- vesa->cmap_write(vesa, i, r16, g16, b16);
- }
- for (i = 32; i < 64; ++i)
- vesa->cmap_write(vesa, i, 0, lut[i * 4 + i / 16].green, 0);
+ drm_crtc_load_gamma_565_from_888(crtc, lut, vesadrm_set_gamma_lut);
break;
case DRM_FORMAT_RGB888:
case DRM_FORMAT_XRGB8888:
case DRM_FORMAT_BGRX8888:
- for (i = 0; i < 256; ++i)
- vesa->cmap_write(vesa, i, lut[i].red, lut[i].green, lut[i].blue);
+ drm_crtc_load_gamma_888(crtc, lut, vesadrm_set_gamma_lut);
break;
default:
drm_warn_once(dev, "Unsupported format %p4cc for gamma correction\n",
@@ -253,13 +225,13 @@ static void vesadrm_crtc_helper_atomic_flush(struct drm_crtc *crtc,
if (crtc_state->enable && crtc_state->color_mgmt_changed) {
if (sysfb_crtc_state->format == sysfb->fb_format) {
if (crtc_state->gamma_lut)
- vesadrm_set_gamma_lut(vesa,
- sysfb_crtc_state->format,
- crtc_state->gamma_lut->data);
+ vesadrm_load_gamma_lut(vesa,
+ sysfb_crtc_state->format,
+ crtc_state->gamma_lut->data);
else
- vesadrm_set_gamma_linear(vesa, sysfb_crtc_state->format);
+ vesadrm_fill_gamma_lut(vesa, sysfb_crtc_state->format);
} else {
- vesadrm_set_gamma_linear(vesa, sysfb_crtc_state->format);
+ vesadrm_fill_gamma_lut(vesa, sysfb_crtc_state->format);
}
}
}
--
2.49.0
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