On Tue, 2018-07-31 at 13:54 +0200, Philipp Zabel wrote:
On Tue, 2018-07-17 at 13:48 +0300, Leonard Crestez wrote:
Adding lcdif nodes to a power domain currently does work, it results in black/corrupted screens or hangs. While the driver does enable runtime pm it does not deal correctly with the block being unpowered.
Ensure power is on when required by adding pm_runtime_get/put_sync to mxsfb_pipe_enable/disable.
Since power is lost on suspend implement PM_SLEEP_OPS using drm_mode_config_helper_suspend/resume.
The mxsfb_plane_atomic_update function can get called before mxsfb_pipe_enable while the block is not yet powered. When this happens the write to LCDIF_NEXT_BUF is lost causing corrupt display on unblank until a refresh.
Why does this happen?
I'm not sure what you're asking but register writes to unpowered or unclocked blocks are not expected to "just work". Here the write is ignored/lost but I think on imx8 it can even cause a bus error.
The approach here is to only set the framebuffer address as part of activating the display.
Fix this by not writing gem->paddr if the block is not enabled and instead delaying the write until the next mxsfb_crtc_mode_set_nofb call. At that point also update cur_buf to avoid an initial corrupt frame after resume.
Signed-off-by: Leonard Crestez leonard.crestez@nxp.com
Tested-by: Philipp Zabel p.zabel@pengutronix.de
on imx6ull-evk, this fixes the initial corrupt frame.
Cool!