Hi Paul, > Am 23.09.2021 um 22:23 schrieb H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>: > > >> Because your "it doesn't work" arguments have zero weight otherwise. > > I hope I still can find it. So I can't promise anything. > We have had it complete in DTS and added code to parse it. > It may have been wiped out by cleaning up patch series during rebase. I was able to locate it and place it on top of your ingenic-drm-drv v3 and our synopsys hdmi v3 [1] (+ unpublished work). This [2] should save you a lot of time making dw-hdmi work on jz4780 at all, so you can focus on our mistakes instead of starting from scratch. Features: - based on v5.15-rc2 - (the first two patches are LetuxOS and build system related and can be ignored for this discussion) - contains some significant patch from drm-next not yet upstream - contains your v3 series as is - (initially) disables your DRM_BRIDGE_ATTACH_NO_CONNECTOR (is reverted in the last patch) - adds synopsys stuff and DT schema - adds jz4780.dtsi and ci20.dts - adds ci20_defconfig - (adds some (optional) jz4780 specific features we likely do not need now) - adds something to dw-hdmi to properly notify HPD - adds a hdmi-regulator so that HPD power can be turned on/off - (attempt to configure the dw-hdmi unwedge feature) - then we add the hdmi-connector to replace the dw-hdmi connector to device tree - and finally re-enable DRM_BRIDGE_ATTACH_NO_CONNECTOR The result is a) without the last patch I get a proper setup with framebuffer and edid. Unfortunateley without any image on HDMI. b) if last patch is included (so that DRM_BRIDGE_ATTACH_NO_CONNECTOR is required as by your [patch v3 6/6] again) I get: [ 4.351200] [drm:drm_bridge_attach [drm]] *ERROR* failed to attach bridge /hdmi@10180000 to encoder DPI-34: -22 [ 4.474346] [drm:drm_bridge_attach [drm]] *ERROR* failed to attach bridge (null) to encoder DPI-34: -22 [ 4.562125] ingenic-drm 13050000.lcdc0: Unable to attach bridge [ 4.568103] ingenic-drm: probe of 13050000.lcdc0 failed with error -22 Maybe you can spot the bug in the code much quicker than we can. I do not know what Paul Boddie did differently if this initialization with connector-hdmi works for him and does not fail likewise. BR and thanks, Nikolaus [1]: https://lore.kernel.org/linux-mips/8e873f17fcc9aeb326d99b7c2c8cd25b61dca6f5.1628399442.git.hns@xxxxxxxxxxxxx/T/ [2]: https://git.goldelico.com/?p=letux-kernel.git;a=shortlog;h=refs/heads/upstream%2Bjz4780%2Bhdmi-connector
