[PATCH v2] drm/ast: Add Atomic gamma lut support for aspeed

Thomas Zimmermann tzimmermann at suse.de
Thu Sep 29 15:27:57 UTC 2022


Hi

Am 29.09.22 um 15:20 schrieb Jocelyn Falempe:
> The current ast driver only supports legacy gamma interface.
> This also fixes a Gnome3/Wayland error which incorrectly adds
> gamma to atomic commit:
> "Page flip discarded: CRTC property (GAMMA_LUT) not found"
> 
> I only tested remotely, so I wasn't able to check that it had
> an effect on the VGA output. But when activating "Night Light"
> in Gnome, ast_crtc_load_lut() is called.
> 
> v2: use the same functions as mgag200.
>      handle 16bits color mode.
> 
> Signed-off-by: Jocelyn Falempe <jfalempe at redhat.com>

That works well on my AST2300 test system. The one thing missing is the 
CRTC's atomic_check code. See

 
https://cgit.freedesktop.org/drm/drm-tip/tree/drivers/gpu/drm/mgag200/mgag200_mode.c#n597

for what to do. With this test implemented, you can add

Tested-by: Thomas Zimmermann <tzimmermann at suse.de>
Reviewed-by: Thomas Zimmermann <tzimmermann at suse.de>

to the patch.

Best regards
Thomas

> ---
>   drivers/gpu/drm/ast/ast_mode.c | 94 ++++++++++++++++++++++++++++------
>   1 file changed, 77 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/ast/ast_mode.c b/drivers/gpu/drm/ast/ast_mode.c
> index 214b10178454..06ea13c3a9b4 100644
> --- a/drivers/gpu/drm/ast/ast_mode.c
> +++ b/drivers/gpu/drm/ast/ast_mode.c
> @@ -49,6 +49,8 @@
>   #include "ast_drv.h"
>   #include "ast_tables.h"
>   
> +#define AST_LUT_SIZE 256
> +
>   static inline void ast_load_palette_index(struct ast_private *ast,
>   				     u8 index, u8 red, u8 green,
>   				     u8 blue)
> @@ -63,20 +65,71 @@ static inline void ast_load_palette_index(struct ast_private *ast,
>   	ast_io_read8(ast, AST_IO_SEQ_PORT);
>   }
>   
> -static void ast_crtc_load_lut(struct ast_private *ast, struct drm_crtc *crtc)
> +static void ast_crtc_set_gamma_linear(struct ast_private *ast,
> +				      const struct drm_format_info *format)
>   {
> -	u16 *r, *g, *b;
>   	int i;
>   
> -	if (!crtc->enabled)
> -		return;
> +	switch (format->format) {
> +	case DRM_FORMAT_RGB565:
> +		/* Use better interpolation, to take 32 values from 0 to 255 */
> +		for (i = 0; i < AST_LUT_SIZE / 8; i++)
> +			ast_load_palette_index(ast,
> +					       i,
> +					       i * 8 + i / 4,
> +					       i * 4 + i / 16,
> +					       i * 8 + i / 4);
> +		/* Green has one more bit, so add padding with 0 for red and blue. */
> +		for (i = AST_LUT_SIZE / 8; i < AST_LUT_SIZE / 4; i++)
> +			ast_load_palette_index(ast, i, 0, i * 4 + i / 16, 0);
> +		break;
> +	case DRM_FORMAT_C8: /* In this case, gamma table is used as color palette */
> +	case DRM_FORMAT_RGB888:
> +	case DRM_FORMAT_XRGB8888:
> +		for (i = 0; i < AST_LUT_SIZE; i++)
> +			ast_load_palette_index(ast, i, i, i, i);
> +		break;
> +	default:
> +		drm_warn_once(&ast->base, "Unsupported format %p4cc for gamma correction\n",
> +			      &format->format);
> +		break;
> +	}
> +}
>   
> -	r = crtc->gamma_store;
> -	g = r + crtc->gamma_size;
> -	b = g + crtc->gamma_size;
> +static void ast_crtc_set_gamma(struct ast_private *ast,
> +			       const struct drm_format_info *format,
> +			       struct drm_color_lut *lut)
> +{
> +	int i;
>   
> -	for (i = 0; i < 256; i++)
> -		ast_load_palette_index(ast, i, *r++ >> 8, *g++ >> 8, *b++ >> 8);
> +	switch (format->format) {
> +	case DRM_FORMAT_RGB565:
> +		/* Use better interpolation, to take 32 values from lut[0] to lut[255] */
> +		for (i = 0; i < AST_LUT_SIZE / 8; i++)
> +			ast_load_palette_index(ast,
> +					       i,
> +					       lut[i * 8 + i / 4].red >> 8,
> +					       lut[i * 4 + i / 16].green >> 8,
> +					       lut[i * 8 + i / 4].blue >> 8);
> +		/* Green has one more bit, so add padding with 0 for red and blue. */
> +		for (i = AST_LUT_SIZE / 8; i < AST_LUT_SIZE / 4; i++)
> +			ast_load_palette_index(ast, i, 0, lut[i * 4 + i / 16].green >> 8, 0);
> +		break;
> +	case DRM_FORMAT_C8: /* In this case, gamma table is used as color palette */
> +	case DRM_FORMAT_RGB888:
> +	case DRM_FORMAT_XRGB8888:
> +		for (i = 0; i < AST_LUT_SIZE; i++)
> +			ast_load_palette_index(ast,
> +					       i,
> +					       lut[i].red >> 8,
> +					       lut[i].green >> 8,
> +					       lut[i].blue >> 8);
> +		break;
> +	default:
> +		drm_warn_once(&ast->base, "Unsupported format %p4cc for gamma correction\n",
> +			      &format->format);
> +		break;
> +	}
>   }
>   
>   static bool ast_get_vbios_mode_info(const struct drm_format_info *format,
> @@ -1018,9 +1071,11 @@ static void ast_crtc_dpms(struct drm_crtc *crtc, int mode)
>   
>   			ast_set_color_reg(ast, format);
>   			ast_set_vbios_color_reg(ast, format, vbios_mode_info);
> +			if (crtc->state->gamma_lut)
> +				ast_crtc_set_gamma(ast, format, crtc->state->gamma_lut->data);
> +			else
> +				ast_crtc_set_gamma_linear(ast, format);
>   		}
> -
> -		ast_crtc_load_lut(ast, crtc);
>   		break;
>   	case DRM_MODE_DPMS_STANDBY:
>   	case DRM_MODE_DPMS_SUSPEND:
> @@ -1158,20 +1213,23 @@ ast_crtc_helper_atomic_flush(struct drm_crtc *crtc,
>   {
>   	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
>   									  crtc);
> -	struct drm_crtc_state *old_crtc_state = drm_atomic_get_old_crtc_state(state,
> -									      crtc);
>   	struct drm_device *dev = crtc->dev;
>   	struct ast_private *ast = to_ast_private(dev);
>   	struct ast_crtc_state *ast_crtc_state = to_ast_crtc_state(crtc_state);
> -	struct ast_crtc_state *old_ast_crtc_state = to_ast_crtc_state(old_crtc_state);
>   	struct ast_vbios_mode_info *vbios_mode_info = &ast_crtc_state->vbios_mode_info;
>   
>   	/*
>   	 * The gamma LUT has to be reloaded after changing the primary
>   	 * plane's color format.
>   	 */
> -	if (old_ast_crtc_state->format != ast_crtc_state->format)
> -		ast_crtc_load_lut(ast, crtc);
> +	if (crtc_state->enable && crtc_state->color_mgmt_changed) {
> +		if (crtc_state->gamma_lut)
> +			ast_crtc_set_gamma(ast,
> +					   ast_crtc_state->format,
> +					   crtc_state->gamma_lut->data);
> +		else
> +			ast_crtc_set_gamma_linear(ast, ast_crtc_state->format);
> +	}
>   
>   	//Set Aspeed Display-Port
>   	if (ast->tx_chip_types & AST_TX_ASTDP_BIT)
> @@ -1309,7 +1367,9 @@ static int ast_crtc_init(struct drm_device *dev)
>   	if (ret)
>   		return ret;
>   
> -	drm_mode_crtc_set_gamma_size(crtc, 256);
> +	drm_mode_crtc_set_gamma_size(crtc, AST_LUT_SIZE);
> +	drm_crtc_enable_color_mgmt(crtc, 0, false, AST_LUT_SIZE);
> +
>   	drm_crtc_helper_add(crtc, &ast_crtc_helper_funcs);
>   
>   	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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