Hi Vicenç, On 12/12/19 23:04, Vicente Bergas wrote: > Hi Enric, Douglas, Sean, > there is an issue on RK3399-based platforms with display flickering. > I have searched mailing list and found you have mentioned or were > involved in related issues, so, you may be able to help. > > The issue has been observed on the Sapphire board and on google kevin, > both are based on the RK3399. The display on Sapphire is connected > through HDMI and on google kevin it's the built-in eDP panel. > > On the Sapphire board i have two bootloaders available: u-boot and > an adaptation of > https://gitlab.com/vicencb/kevinboot > which is a linux-based bootloader by means of kexec. > > On google kevin i only have one bootloader: kevinboot with kexec. > > When running the first kernel (before kexec) or when booting with > u-boot the display works fine. > > The issue appears when running the second kernel (after kexec). > I have observed two kinds of flickering, sometimes it is just bursts > of horizontal dark lines and sometimes it is the whole screen > becoming black for less than a second. > It happens very often, each time there is a big portion of the screen > being updated, like, e.g. scrolling a text file or a web page in full > screen mode. > > Do you have any ideas on what the root cause of the issue could be? > To be honest, I don't have idea, looks like some clock configuration issue? Did you check the clock after and before? I might be interested to look a bit more into the issue if this is reproducible using the coreboot bootloader. Do you know if this happens with stock bootloader? Thanks, Enric > Regards, > Vicenç. > _______________________________________________ Linux-rockchip mailing list Linux-rockchip@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-rockchip
