From: Max Krummenacher [mailto:max.oss.09@xxxxxxxxx] Sent: Wednesday, February 9, 2022 10:38 AM >> If display timings were read from the devicetree using >> of_get_display_timing() and pixelclk-active is defined >> there, the flag DISPLAY_FLAGS_SYNC_POSEDGE/NEGEDGE is >> automatically generated. Through the function >> drm_bus_flags_from_videomode() e.g. called in the >> panel-simple driver this flag got into the bus flags, >> but then in imx_pd_bridge_atomic_check() the bus flag >> check failed and will not initialize the display. The >> original commit fe141cedc433 does not explain why this >> check was introduced. So remove the bus flags check, >> because it stops the initialization of the display with >> valid bus flags. >> >> Fixes: fe141cedc433 ("drm/imx: pd: Use bus format/flags provided by the bridge when available") >> Signed-off-by: Christoph Niedermaier <cniedermaier@xxxxxxxxxxxxxxxxxx> >> Cc: Marek Vasut <marex@xxxxxxx> >> Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx> >> Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> >> Cc: David Airlie <airlied@xxxxxxxx> >> Cc: Daniel Vetter <daniel@xxxxxxxx> >> Cc: Shawn Guo <shawnguo@xxxxxxxxxx> >> Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> >> Cc: Pengutronix Kernel Team <kernel@xxxxxxxxxxxxxx> >> Cc: Fabio Estevam <festevam@xxxxxxxxx> >> Cc: NXP Linux Team <linux-imx@xxxxxxx> >> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx >> To: dri-devel@xxxxxxxxxxxxxxxxxxxxx >> --- >> V2: - Add Boris to the Cc list >> --- >> drivers/gpu/drm/imx/parallel-display.c | 8 -------- >> 1 file changed, 8 deletions(-) >> >> diff --git a/drivers/gpu/drm/imx/parallel-display.c b/drivers/gpu/drm/imx/parallel-display.c >> index a8aba0141ce7..06cb1a59b9bc 100644 >> --- a/drivers/gpu/drm/imx/parallel-display.c >> +++ b/drivers/gpu/drm/imx/parallel-display.c >> @@ -217,14 +217,6 @@ static int imx_pd_bridge_atomic_check(struct drm_bridge *bridge, >> if (!imx_pd_format_supported(bus_fmt)) >> return -EINVAL; >> >> - if (bus_flags & >> - ~(DRM_BUS_FLAG_DE_LOW | DRM_BUS_FLAG_DE_HIGH | >> - DRM_BUS_FLAG_PIXDATA_DRIVE_POSEDGE | >> - DRM_BUS_FLAG_PIXDATA_DRIVE_NEGEDGE)) { >> - dev_warn(imxpd->dev, "invalid bus_flags (%x)\n", bus_flags); >> - return -EINVAL; >> - } >> - >> bridge_state->output_bus_cfg.flags = bus_flags; >> bridge_state->input_bus_cfg.flags = bus_flags; >> imx_crtc_state->bus_flags = bus_flags; > > Tested on a Colibri iMX6DL with a panel-dpi based panel. > > Tested-by: Max Krummenacher <max.krummenacher@xxxxxxxxxxx> I still ask myself why this bus flag check is in the code. Is there a reason not to remove that? Regards Christoph
