[PATCH v2] mgag200: Enable atomic gamma lut update
Thomas Zimmermann
tzimmermann at suse.de
Thu May 12 08:52:57 UTC 2022
Hi
Am 11.05.22 um 17:28 schrieb Jocelyn Falempe:
> Add support for atomic update of gamma lut.
> With this patch the "Night light" feature of gnome3
> is working properly on mgag200.
>
> v2:
> - Add a default linear gamma function
> - renamed functions with mgag200 prefix
> - use format's 4cc code instead of bit depth
> - use better interpolation for 16bits gamma
> - remove legacy function mga_crtc_load_lut()
> - can't remove the call to drm_mode_crtc_set_gamma_size()
> because it doesn't work with userspace.
> - other small refactors
>
> Signed-off-by: Jocelyn Falempe <jfalempe at redhat.com>
I already gave a Tested-by on the first iteration. It's good practice to
add these tags in follow-up patches unless the patch has changed entirely.
A few more comments are below. With those fixed:
Reviewed-by: Thomas Zimmermann <tzimemrmann at suse.de>
I suggest to post another version of the patch and merge it if no
further comments arrive within 2 days.
> ---
> drivers/gpu/drm/mgag200/mgag200_mode.c | 125 ++++++++++++++++---------
> 1 file changed, 81 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/gpu/drm/mgag200/mgag200_mode.c b/drivers/gpu/drm/mgag200/mgag200_mode.c
> index 6e18d3bbd720..b748bc5b0e93 100644
> --- a/drivers/gpu/drm/mgag200/mgag200_mode.c
> +++ b/drivers/gpu/drm/mgag200/mgag200_mode.c
> @@ -32,57 +32,76 @@
> * This file contains setup code for the CRTC.
> */
>
> -static void mga_crtc_load_lut(struct drm_crtc *crtc)
> +static void mgag200_crtc_set_gamma_linear(struct mga_device *mdev,
> + uint32_t format)
> {
> - struct drm_device *dev = crtc->dev;
> - struct mga_device *mdev = to_mga_device(dev);
> - struct drm_framebuffer *fb;
> - u16 *r_ptr, *g_ptr, *b_ptr;
> int i;
>
> - if (!crtc->enabled)
> - return;
> -
> - if (!mdev->display_pipe.plane.state)
> - return;
> + WREG8(DAC_INDEX + MGA1064_INDEX, 0);
>
> - fb = mdev->display_pipe.plane.state->fb;
> + switch (format) {
> + case DRM_FORMAT_RGB565:
> + /* Use better interpolation, to take 32 values from 0 to 255 */
> + for (i = 0; i < MGAG200_LUT_SIZE / 8; i++) {
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, i * 8 + i / 4);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, i * 4 + i / 16);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, i * 8 + i / 4);
> + }
> + /* Green has one more bit, so add padding with 0 for red and blue. */
> + for (i = MGAG200_LUT_SIZE / 8; i < MGAG200_LUT_SIZE / 4; i++) {
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, 0);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, i * 4 + i / 16);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, 0);
> + }
> + break;
> + case DRM_FORMAT_RGB888:
> + case DRM_FORMAT_XRGB8888:
> + for (i = 0; i < MGAG200_LUT_SIZE; i++) {
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, i);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, i);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, i);
> + }
These loops look much nicer to me.
> + break;
> + default:
> + drm_warn_once(&mdev->base, "Unsupported format for gamma %d\n", format);
There's a print format modifier for 4cc formats. It's %p4cc and expects
a pointer to the format's 4cc code. See 'git grep p4cc' for examples.
The comment itself is not easy to understand. Maybe "Unsupported format
%p4cc for gamma correction.\n" ?
> + break;
> + }
> +}
>
> - r_ptr = crtc->gamma_store;
> - g_ptr = r_ptr + crtc->gamma_size;
> - b_ptr = g_ptr + crtc->gamma_size;
> +static void mgag200_crtc_set_gamma(struct mga_device *mdev,
> + struct drm_color_lut *lut,
> + uint32_t format)
> +{
> + int i;
>
> WREG8(DAC_INDEX + MGA1064_INDEX, 0);
>
> - if (fb && fb->format->cpp[0] * 8 == 16) {
> - int inc = (fb->format->depth == 15) ? 8 : 4;
> - u8 r, b;
> - for (i = 0; i < MGAG200_LUT_SIZE; i += inc) {
> - if (fb->format->depth == 16) {
> - if (i > (MGAG200_LUT_SIZE >> 1)) {
> - r = b = 0;
> - } else {
> - r = *r_ptr++ >> 8;
> - b = *b_ptr++ >> 8;
> - r_ptr++;
> - b_ptr++;
> - }
> - } else {
> - r = *r_ptr++ >> 8;
> - b = *b_ptr++ >> 8;
> - }
> - /* VGA registers */
> - WREG8(DAC_INDEX + MGA1064_COL_PAL, r);
> - WREG8(DAC_INDEX + MGA1064_COL_PAL, *g_ptr++ >> 8);
> - WREG8(DAC_INDEX + MGA1064_COL_PAL, b);
> + switch (format) {
> + case DRM_FORMAT_RGB565:
> + /* Use better interpolation, to take 32 values from lut[0] to lut[255] */
> + for (i = 0; i < MGAG200_LUT_SIZE / 8; i++) {
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, lut[i * 8 + i / 4].red >> 8);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, lut[i * 4 + i / 16].green >> 8);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, lut[i * 8 + i / 4].blue >> 8);
> }
> - return;
> - }
> - for (i = 0; i < MGAG200_LUT_SIZE; i++) {
> - /* VGA registers */
> - WREG8(DAC_INDEX + MGA1064_COL_PAL, *r_ptr++ >> 8);
> - WREG8(DAC_INDEX + MGA1064_COL_PAL, *g_ptr++ >> 8);
> - WREG8(DAC_INDEX + MGA1064_COL_PAL, *b_ptr++ >> 8);
> + /* Green has one more bit, so add padding with 0 for red and blue. */
> + for (i = MGAG200_LUT_SIZE / 8; i < MGAG200_LUT_SIZE / 4; i++) {
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, 0);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, lut[i * 4 + i / 16].green >> 8);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, 0);
> + }
> + break;
> + case DRM_FORMAT_RGB888:
> + case DRM_FORMAT_XRGB8888:
> + for (i = 0; i < MGAG200_LUT_SIZE; i++) {
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, lut[i].red >> 8);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, lut[i].green >> 8);
> + WREG8(DAC_INDEX + MGA1064_COL_PAL, lut[i].blue >> 8);
> + }
> + break;
> + default:
> + drm_warn_once(&mdev->base, "Unsupported format for gamma %d\n", format);
Same as above.
> + break;
> }
> }
>
> @@ -900,7 +919,11 @@ mgag200_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe,
> if (mdev->type == G200_WB || mdev->type == G200_EW3)
> mgag200_g200wb_release_bmc(mdev);
>
> - mga_crtc_load_lut(crtc);
> + if (crtc_state->gamma_lut)
> + mgag200_crtc_set_gamma(mdev, crtc_state->gamma_lut->data, fb->format->format);
Nitpicking: I'd give the format before the LUT data. It's more logical
and aligns with '_set_gamma_linear'. I'd also pass fb->format instead of
fb->format->format.
> + else
> + mgag200_crtc_set_gamma_linear(mdev, fb->format->format);
> +
> mgag200_enable_display(mdev);
>
> mgag200_handle_damage(mdev, fb, &fullscreen, &shadow_plane_state->data[0]);
> @@ -945,6 +968,14 @@ mgag200_simple_display_pipe_check(struct drm_simple_display_pipe *pipe,
> return ret;
> }
>
> + if (crtc_state->color_mgmt_changed && crtc_state->gamma_lut) {
> + if (crtc_state->gamma_lut->length !=
> + MGAG200_LUT_SIZE * sizeof(struct drm_color_lut)) {
> + drm_err(dev, "Wrong size for gamma_lut %ld\n",
The kernel bot complained about '%ld'. I think %zu is the one for size_t.
> + crtc_state->gamma_lut->length);
> + return -EINVAL;
> + }
> + }
> return 0;
> }
>
> @@ -953,6 +984,7 @@ mgag200_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
> struct drm_plane_state *old_state)
> {
> struct drm_plane *plane = &pipe->plane;
> + struct drm_crtc *crtc = &pipe->crtc;
> struct drm_device *dev = plane->dev;
> struct mga_device *mdev = to_mga_device(dev);
> struct drm_plane_state *state = plane->state;
> @@ -963,6 +995,9 @@ mgag200_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
> if (!fb)
> return;
>
> + if (crtc->state->color_mgmt_changed && crtc->state->gamma_lut)
> + mgag200_crtc_set_gamma(mdev, crtc->state->gamma_lut->data, fb->format->format);
> +
This also needs a call to _set_gamma_linear?
Best regards
Thomas
> if (drm_atomic_helper_damage_merged(old_state, state, &damage))
> mgag200_handle_damage(mdev, fb, &damage, &shadow_plane_state->data[0]);
> }
> @@ -1107,9 +1142,11 @@ int mgag200_modeset_init(struct mga_device *mdev)
> return ret;
> }
>
> - /* FIXME: legacy gamma tables; convert to CRTC state */
> + /* FIXME: legacy gamma tables, but atomic gamma doesn't work without */
> drm_mode_crtc_set_gamma_size(&pipe->crtc, MGAG200_LUT_SIZE);
>
> + drm_crtc_enable_color_mgmt(&pipe->crtc, 0, false, MGAG200_LUT_SIZE);
> +
> drm_mode_config_reset(dev);
>
> return 0;
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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