2016-09-29 20:40 GMT+02:00 Karl Beldan <karl.bel...@gmail.com>: > Hi, > > On Thu, Sep 29, 2016 at 06:31:52PM +0200, Bartosz Golaszewski wrote: >> From: Karl Beldan <kbel...@baylibre.com> >> >> This adds the pins used by the LCD controller, and uses 'tilcdc,panel' >> with some default timings for 800x600. >> >> Tested on an LCDK connected on the VGA port (the LCDC is connected to >> this port via a THS8135). >> >> Signed-off-by: Karl Beldan <kbel...@baylibre.com> >> [Bartosz: >> - fixed whitespace errors >> - tweaked the description > > The description tweak you mention is the removal of an erratum which is > in the mentioned commit I put on github @ > (https://github.com/kbeldan/linux/commit/b7720bc983c00a083dece119f68ea9d2f522c6c4) > it included an erratum wrt FIFO threshold I think is worth keeping: > { > There is an erratum (fifo-th) "LCDC: Underflow During Initialization": > [...] > "This problem may occur if the LCDC FIFO threshold size ( > LCDDMA_CTRL[TH_FIFO_READY]) is left at its default value after reset. > Increasing the FIFO threshold size will reduce or eliminate underflows. > Setting the threshold size to 256 double words or larger is > recommended." > }
Isn't this the issue that is fixed by changing the memory priority for lcdc? > >> - fixed the incorrect hback-porch value > > It can't be a fix, this value depends on the monitor connected. > Thanks, I'm new to drm. From reading the datasheet it seemed to me that this depends on the resolution. FWIW it seems that most LCDs are able to adjust to this themselves - I tested with two different displays and the value I introduced worked on both while the previous one shifted the image to the right. I'll look into that. >> - other minor tweaks] > > I didn't see any other change while diffing. > Dropped the refresh rate from the timings node name. Thanks, Bartosz
