who knows details about the new linux drm bridge and connector stuff? i'm in the process of updating my Reform patches to kernel 5.7+ and my nwl-dsi -> sn65dsi86 -> edp chain doesn't work anymore. i think the bridges are waiting for each other. DTS excerpt: https://gist.github.com/mntmn/2c04a16f8dfb8f9a19170194539cdfd7#file-mntreform2-dts-displaybridges-dts-L108
@agx ah, i think i'm just missing CONFIG_MUX_MMIO
@agx ok, now nwl-dsi is selecting LCDIF instead of DCSS.
@agx ah, this is how to select DCSS in the DTS. now nwl-dsi does the right thing, but ti_sn_bridge_attach() is still never called.
@agx oh, looks like kernel make doesn't actually build the dcss sources.
@agx many printk()s later. figured out that DCSS is silently not built because CONFIG_DRM_IMX is not a thing for imx8m but dcss is in gpu/drm/imx/dcss. added obj-$(CONFIG_DRM_IMX_DCSS) += imx/ to the Makefile as a workaround
@agx i see this was adressed in v4 of the DCSS patch. all good now. to get something on screen and not a blank image i had to remove this polarity hack in nwl-dsi.c. so this works only for LCDIF, not for DCSS.
@mntmn yes, dcss and mxsfb disagree about polarity: https://source.codeaurora.org/external/imx/linux-imx/tree/drivers/gpu/drm/bridge/nwl-dsi/nwl-drv.c?h=imx_5.4.0_8dxlphantom_er#n480
