Hi, On Thu, Jul 16, 2020 at 04:32:09PM +0200, Ondřej Jirman wrote: > Hi Guido, > > On Thu, Jul 16, 2020 at 04:08:43PM +0200, Guido Günther wrote: > > Hi Ondrej, > > On Thu, Jul 16, 2020 at 02:37:51PM +0200, Ondrej Jirman wrote: > > > When extending the driver for xbd599 panel support I tried to do minimal > > > changes and keep the existing initialization timing. > > > > > > It turned out that it's not good enough and the existing init sequence > > > is too aggressive and doesn't follow the specification. On PinePhone > > > panel is being powered down/up during suspend/resume and with current > > > timings this frequently leads to corrupted display. > > > > Given the amount of ST7703 look alikes i don't think you can go by the > > datasheet and hope not to break other panels. The current sleeps cater > > for the rocktech panel (which suffered from similar issues you describe > > when we took other parameters) so you need to make those panel specific. > > It should work on rocktech too. The patch mostly increases/reorders the delays > slightly, to match the controller documentation. I don't see a reason to > complicate the driver with per panel special delays, unless these patches don't > work on your panel. That's why i brought it up. It breaks the rocktech panel on blank/unblank loops where it just stays blank and then starts hitting DSI command timeouts. Cheers, -- Guido > > The init sequence is still suboptimal, and doesn't follow the kernel docs > completely, even after these patches. Controller spec also talks about adding > some delay before enabling the backlight to avoid visual glitches. > > Which is what enable callback is documented to be for. Currently part of the > initialization that belongs to prepare callback is also done in enable callback. > > I see the glitch (small vertical shift of the image on powerup), but personally > don't care much to introduce even more delays to the driver, just for the > cosmetic issue. > > regards, > o. > > > Cheers, > > -- Guido > > > > > > > > This patch series fixes the problems. > > > > > > The issue was reported by Samuel Holland. > > > > > > Relevant screenshots from the datasheet: > > > > > > Power on timing: https://megous.com/dl/tmp/35b72e674ce0ca27.png > > > Power off timing: https://megous.com/dl/tmp/dea195517106ff17.png > > > More optimal reset on poweron: https://megous.com/dl/tmp/a9e5caf14e1b0dc6.png > > > Less optimal reset on poweron: https://megous.com/dl/tmp/246761039283c4cf.png > > > Datasheet: https://megous.com/dl/tmp/ST7703_DS_v01_20160128.pdf > > > > > > Please take a look. > > > > > > thank you and regards, > > > Ondrej Jirman > > > > > > Ondrej Jirman (2): > > > drm/panel: st7703: Make the sleep exit timing match the spec > > > drm/panel: st7703: Fix the power up sequence of the panel > > > > > > drivers/gpu/drm/panel/panel-sitronix-st7703.c | 29 ++++++++++--------- > > > 1 file changed, 15 insertions(+), 14 deletions(-) > > > > > > -- > > > 2.27.0 > > > > _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
