Re: [PATCH v12 00/18] drm: Add Samsung MIPI DSIM bridge

Marek Vasut
2023-02-07T09:24:31Z

On 2/7/23 10:09, Rasmus Villemoes wrote:

[...]

> Now hotplug-detect doesn't work with the current sn65dsi86 driver, but
> that's a separate issue; when I boot with a monitor attached, its edid
> is correctly read out. But I still don't get any output, and the monitor
> says "no signal" - my naive attempt (which has worked fine in other
> cases) was to just dd /dev/urandom to /dev/fb0, so I'm clearly missing
> some important step.

You could try and tweak the DSI mode flags in
drivers/gpu/drm/bridge/ti-sn65dsi86.c to operate in DSI burst mode
MIPI_DSI_MODE_VIDEO_BURST instead of MIPI_DSI_MODE_VIDEO . Then you
could configure the DSIM PLL to 891 MHz , but you also have to make sure
the DSI86 would expect the 891 MHz (please check the datasheet).

Try and look up patches below for related approach:
drm/bridge: ti-sn65dsi83: Add and use hs_rate and lp_rate
drm: bridge: samsung-dsim: Select DSI HS clock rate from downstream
bridge limits