On Wed, Sep 29, 2021 at 5:36 AM Brian Norris briannorris@chromium.org wrote:
In commit 43c2de1002d2, we moved most HW configuration to bind(), but we didn't move the runtime PM management. Therefore, depending on initial boot state, runtime-PM workqueue delays, and other timing factors, we may disable our power domain in between the hardware configuration (bind()) and when we enable the display. This can cause us to lose hardware state and fail to configure our display. For example:
dw-mipi-dsi-rockchip ff968000.mipi: failed to write command FIFO panel-innolux-p079zca ff960000.mipi.0: failed to write command 0
or:
dw-mipi-dsi-rockchip ff968000.mipi: failed to write command FIFO panel-kingdisplay-kd097d04 ff960000.mipi.0: failed write init cmds: -110
We should match the runtime PM to the lifetime of the bind()/unbind() cycle.
Tested on Acer Chrometab 10 (RK3399 Gru-Scarlet), with panel drivers built either as modules or built-in.
Side notes: it seems one is more likely to see this problem when the panel driver is built into the kernel. I've also seen this problem bisect down to commits that simply changed Kconfig dependencies, because it changed the order in which driver init functions were compiled into the kernel, and therefore the ordering and timing of built-in device probe.
Fixes: 43c2de1002d2 ("drm/rockchip: dsi: move all lane config except LCDC mux to bind()") Link: https://lore.kernel.org/linux-rockchip/9aedfb528600ecf871885f7293ca4207c84d1... Reported-by: aleksandr.o.makarov@gmail.com Cc: stable@vger.kernel.org Signed-off-by: Brian Norris briannorris@chromium.org Tested-by: Nícolas F. R. A. Prado nfraprado@collabora.com
Reviewed-by: Chen-Yu Tsai wenst@chromium.org