[Letux-kernel] DSI & DPI panels with omapdrm on 4.20-rc

Laurent Pinchart laurent.pinchart at ideasonboard.com
Fri Nov 23 15:06:18 CET 2018


On Friday, 16 November 2018 14:46:24 EET Tomi Valkeinen wrote:
> On 15/11/18 17:50, H. Nikolaus Schaller wrote:
> > Am 15.11.2018 um 12:17 schrieb Tomi Valkeinen:
> >> On 15/11/18 08:00, H. Nikolaus Schaller wrote:
> >>> But also DISPC_POL_FREQ.
> >> 
> >> Can you try the attached hack patch?
> > 
> > Seems to fix something. I now have a desktop back on the panel :)
> Ok. I need to discuss with Laurent about this when he gets back.

When reworking the timings code I failed to notice that bus flags were 
retrieved from DT for panel-dpi :-( My apologies about that.

Tomi, your patch looks fine to me. My only comment is that I would move the 
drm_bus_flags_from_videomode() call to panel_dpi_probe(), right after setting 
dssdev->of_ports, to be consistent with the other drivers.

> > What I have observed is that the panel dimensions in mm seem to have
> > changed (because our GUI software uses that as a scaling factor).
> Which panel driver is this? Does "changed" mean that they were correct
> previously, and not anymore? What are/were the numbers?
> > When reworking the dsi panel drivers, I have seen that panel drivers
> > can now report the dimensions in mm. So does the generic DPI driver have
> > a new default here? Can it be specified by new DT properties?
> > But I have to check that I do not have a user-space bug here.
> panel-dpi.c has not and does not supported physical size. There's code
> in omap_connector.c that calls get_size() to get the size. You could add
> debug prints there to see if it's called and what are the numbers.
> > How does omapdrm X11 handle the mouse cursor? By an overlay of the
> > OMAP3 DSS? Then there may be some other bits for the overlay priority
> > depend on driver probe sequence (the td028ttec1 is probed as an SPI
> > client, probably before omapdrm but I don't know).
> If I recall right, omap xdriver has a config option for HW or SW cursor,
> and HW cursor uses a plane with legacy modesetting to show the cursor.
> HW cursor has always been buggy, but apparently something has changed,
> causing the plane not to be transparent.


Laurent Pinchart

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