On Thu, Oct 3, 2019 at 12:21 PM Icenowy Zheng icenowy@aosc.io wrote:
于 2019年10月3日 GMT+08:00 下午2:45:21, Jagan Teki jagan@amarulasolutions.com 写到:
The LCD timing definitions between Linux DRM vs Allwinner are different, below diagram shows this clear differences.
Active Front Sync Back Region Porch Porch<-----------------------><----------------><--------------><--------------> //////////////////////| ////////////////////// | ////////////////////// |.................. ................ ________________ <----- [hv]display -----> <------------- [hv]sync_start ------------> <--------------------- [hv]sync_end ----------------------> <-------------------------------- [hv]total ------------------------------>
<----- lcd_[xy] --------> <- lcd_[hv]spw -> <---------- lcd_[hv]bp ---------> <-------------------------------- lcd_[hv]t ------------------------------>
The DSI driver misinterpreted the hbp term from the BSP code to refer only to the backporch, when in fact it was backporch + sync. Thus the driver incorrectly used the horizontal front porch plus sync in its calculation of the DRQ set bit value, when it should not have included the sync timing.
Including additional sync timings leads to flip_done timed out as:
I don't think attaching this error infomation is useful at all.
Since the error would be common irrespective of panels and it would trigger from dsi controller, I thought this would be useful for reference. I have had this conversation in previous version changes, so I have added it. let me know if have any comments.