[Intel-gfx] (no subject)

[Linus Walleij]

On Wed, Feb 26, 2020 at 12:57 PM Ville Syrjälä
<ville.syrjala at linux.intel.com> wrote:
> On Tue, Feb 25, 2020 at 10:52:25PM +0100, Linus Walleij wrote:

> > I have long suspected that a whole bunch of the "simple" displays
> > are not simple but contains a display controller and memory.
> > That means that the speed over the link to the display and
> > actual refresh rate on the actual display is asymmetric because
> > well we are just updating a RAM, the resolution just limits how
> > much data we are sending, the clock limits the speed on the
> > bus over to the RAM on the other side.
>
> IMO even in command mode mode->clock should probably be the actual
> dotclock used by the display. If there's another clock for the bus
> speed/etc. it should be stored somewhere else.

Good point. For the DSI panels we have the field hs_rate
for the HS clock in struct mipi_dsi_device which is based
on exactly this reasoning. And that is what I actually use for
setting the HS clock.

The problem is however that we in many cases have so
substandard documentation of these panels that we have
absolutely no idea about the dotclock. Maybe we should
just set it to 0 in these cases?

Yours,
Linus Walleij