Hi,
Am 12.11.2018 um 21:09 schrieb Sebastian Reichel sre@kernel.org:
Hi,
On Mon, Nov 12, 2018 at 10:30:21AM -0800, Tony Lindgren wrote:
- H. Nikolaus Schaller hns@goldelico.com [181112 17:35]:
4.20-rc1 seems to have broken our DSI panel driver for the OMAP5 Pyra.
Laurent's patches break omapdrm DSI support in 4.20 (please read as factual information, not as insult). Note, that there is no working mainline user of this, so technically its not a user visible regression.
Yes, but makes the same problems for out-of tree users :)
The Pyra is planned to become a mainline user of omapdrm.dsi, but as long as there are only a handful of prototypes it is still too early to submit (parts of) the DTS. I think it is more convincing for inclusion if mass production of the hardware is already running.
There were some omapdrm API changes which I have tried to fix by inspecting panel-dsi-cm.c and also comparing with panel-tpo-td028ttec1.c (which is still working on our omap3 systems).
I also have removed the tiler patches by Matthijs to make sure that they do not have an influence.
The strange thing is that the panel driver module is not even loaded during probe time, although we have defined the display alias and not changed that compared to 4.19.
The other strange thing is that I can manually modprobe the driver and it is loaded and shown by lsmod, but the probe function is never called.
Any hints what we should check and compare and verify?
This is probably fixed by the following patch, which depends on Laurent's fixes from a few days ago:
https://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-n900.git/commit/?h...
Yeah! It now loads the panel driver again:
[ 10.344961] dsi: w677l_probe_of() [ 10.628239] dsi: w677l_connect()
The latter ends in a NULL pointer deref, but this is obviously my fault when converting the driver to the new API. And I can debug that now.
Did the panel driver compatible matching mechanism change for dsi panels without a bus (dpi panels are usually loaded as an spi bus client)?
Or is there a new CONFIG that must be set?
Test with Laurent's fixes, and also looks like Sebastian also has some recent yet to be posted probe order changes on top of Laurent's fixes in his linux-n900 branch if Laurent's fixes alone don't help.
Laurent's patches are "[PATCH v3 0/4] omapdrm: Fix runtime PM issues at module load and unload time" and Sebastian's git tree is at https://git.kernel.org/pub/scm/linux/kernel/git/sre/linux-n900.git/.
Adding Laurent and Sebastian to Cc too.
I hope to send a new patchset fixing panel-dsi-cm support in omapdrm later this week (assuming, that nothing unexpected happens).
-- Sebastian
BR and thanks, Nikolaus