On Tue, 2020-08-11 at 14:50 +0000, Stefan Birkholz wrote:
Hello,
we are using the mainline kernel (currently on 4.19.128) successfully on an i.MX6DL-based system, but when we try to upgrade to any more recent kernel (>5.1) the display output stops working (screen is blank, backlight works).
The relevant entries from the kernel log seem to be: [ 8.954942] imx-drm display-subsystem: bound imx-ipuv3-crtc.3 (ops imx_drm_exit [imxdrm]) [ 9.028406] imx-drm display-subsystem: failed to bind disp0 (ops imx_pd_ops [parallel_display]): -517 [ 9.037873] imx-drm display-subsystem: master bind failed: -517
The only call in imx_pd_bind() I would expect to return -EPROBE_DEFER is drm_of_find_panel_or_bridge(), maybe parallel-display node's port@1 is connected to a panel that is not registered. Are the drivers for the panel and all its dependencies (power supply regulator, backlight) enabled and probed?
regards Philipp