On Wed, 10 Dec 2025 19:10:45 +0100 "Luca Ceresoli" <[email protected]> wrote:
> Hi Köry, > > On Wed Nov 26, 2025 at 6:35 PM CET, Kory Maincent (TI.com) wrote: > > The tilcdc hardware does not generate VESA-compliant sync signals. It > > aligns the vertical sync (VS) on the second edge of the horizontal sync > > (HS) instead of the first edge. To compensate for this hardware > > behavior, the driver applies a timing adjustment in mode_fixup(). > > > > Previously, this adjustment was conditional based on the simulate_vesa_sync > > flag, which was only set when using external encoders. This appears > > problematic because: > > > > 1. The timing adjustment seems needed for the hardware behavior regardless > > of whether an external encoder is used > > 2. The external encoder infrastructure is driver-specific and being > > removed due to design issues > > 3. Boards using tilcdc without bridges (e.g., am335x-evm, am335x-evmsk) > > may not be getting the necessary timing adjustments > > > > Remove the simulate_vesa_sync flag and apply the VESA sync timing > > adjustment unconditionally, ensuring consistent behavior across all > > configurations. While it's unclear if the previous conditional behavior > > was causing actual issues, the unconditional adjustment better reflects > > the hardware's characteristics. > > > > Signed-off-by: Kory Maincent (TI.com) <[email protected]> > > --- > > > > Only few board currently use tilcdc not associated to a bridge like the > > am335x_evm or the am335x-evmsk. > > Have you tested this change on any affected board? > > The change looks good to me but without some testing it would be risky. I have tested it on few boards but not these mainline devicetree as I don't have them. I have tested a tilcdc with tda998x bridge (BeagleBone Black), a tilcdc with ti,tilcdc,panel panel (BeagleBone with LCD cape), a tilcdc with it66121 bridge (new Beagle Bone Green Eco board with HDMI cape). That's all the boards I have. Regards, -- Köry Maincent, Bootlin Embedded Linux and kernel engineering https://bootlin.com
