Hi Laurent, On Thu Mar 26, 2026 at 9:28 AM CET, Laurent Pinchart wrote:
>> Many dts files for imx8mp-based boards in the kernel have such a connector >> described and linked to port@1, so a connector is added by the >> display-connector driver along with a bridge wrapping it. Sadly some of >> those dts files don't have the connector described. Adding it would solve >> the problem easily, but this would break existing devices which do not >> update the dtb when upgrading to a newer kernel. > > I think this series should also fix the in-tree dts files, to pave the > way for removing the workaround. Fixing all dts files can surely be done, but it won't allow removing the workaround. Any devices shipped with a dtb without the connector and upgrading their kernel later on but not the dtb will fail as soon as they upgrade to a kernel with patch 8 but with this workaround removed. That said, do you still think it's worth adding the hdmi-connector node to all dtbs missing it? It should be fairly simple and IIRC it would involve a couple dozen drivers at most based on my initial research. However for most of them I have no way to know which type of connector is installed, would it be OK if we describe type A when the type is unknown, just like dw_hdmi_connector_create() does right now programmatically [0]? [0] https://elixir.bootlin.com/linux/v7.0-rc5/source/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c#L2601 Also, if such a change is to be done, I'd definitely do it as a separate series, to avoid adding more stuff to this series in-flight. >> --- a/drivers/gpu/drm/bridge/imx/Kconfig >> +++ b/drivers/gpu/drm/bridge/imx/Kconfig >> @@ -25,6 +25,23 @@ config DRM_IMX8MP_DW_HDMI_BRIDGE >> Choose this to enable support for the internal HDMI encoder found >> on the i.MX8MP SoC. >> >> +config DRM_IMX8MP_DW_HDMI_BRIDGE_CONNECTOR_FIXUP >> + bool "Support device tree blobs without an hdmi-connector node" >> + default y > > Can't we enable the workaround unconditionally ? Distributions will need > to enable this option anyway as they can't know what device they will > boot on. I fear a configuration option will confuse users and waste time > on debugging. Sure, good point. Luca -- Luca Ceresoli, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
