Re: [PATCH v4 10/10] drm/ingenic: add some jz4780 specific features

Am 28.09.2021 um 12:06 schrieb H. Nikolaus Schaller [off-list ref]:

quoted

quoted

+
+	/* RGB output control may be superfluous. */
+	if (soc_info->has_rgbc)
+		regmap_write(priv->map, JZ_REG_LCD_RGBC,
+			     JZ_LCD_RGBC_RGB_FORMAT_ENABLE |
+			     JZ_LCD_RGBC_ODD_RGB |
+			     JZ_LCD_RGBC_EVEN_RGB);

ingenic-drm only supports RGB output right now, so I guess the RGB_FORMAT_ENABLE bit needs to be set in patch [2/10], otherwise patch [2/10] cannot state that it adds support for the JZ4780, if it doesn't actually work.

interestingly it works without setting anything in this register.

quoted

The other two bits can be dropped, they are already set in ingenic_drm_encoder_atomic_mode_set().

Ok.

Setting it manually doesn't change anything visible:

root@letux:~# devmem2 0x13050090
/dev/mem opened.
Memory mapped at address 0x77e14000.
Value at address 0x13050090 (0x77e14090): 0x0
root@letux:~# devmem2 0x13050090 w 0x80
/dev/mem opened.
Memory mapped at address 0x77e38000.
Value at address 0x13050090 (0x77e38090): 0x0
Written 0x80; readback 0x80
root@letux:~# 

Same for 0x130A0090. Maybe this lcdc register
is not used at all - at least for HDMI?

So I'd suggest to drop this whole patch from v5.

BR and thanks,
Nikolaus