On Wed, Nov 19, 2025 at 07:49:23PM +0200, Cristian Ciocaltea wrote: > On 11/19/25 6:24 PM, Chris Morgan wrote: > > On Wed, Nov 19, 2025 at 10:02:23AM +0100, Maxime Ripard wrote: > >> On Tue, Nov 18, 2025 at 02:36:09PM -0600, Chris Morgan wrote: > >>> On Tue, Nov 18, 2025 at 09:46:04AM +0100, Maxime Ripard wrote: > >>>> Hi, > >>>> > >>>> On Thu, Nov 13, 2025 at 01:29:38PM -0600, Chris Morgan wrote: > >>>>> From: Chris Morgan <[email protected]> > >>>>> > >>>>> Add support for the dw-hdmi-qp driver to handle devices with missing > >>>>> HPD pins. > >>>>> > >>>>> Since in this situation we are now polling for the EDID data via i2c > >>>>> change the error message to a debug message when we are unable to > >>>>> complete an i2c read, as a disconnected device would otherwise fill > >>>>> dmesg with i2c read errors. > >>>>> > >>>>> Signed-off-by: Chris Morgan <[email protected]> > >>>> > >>>> You must also disable any mode using the scrambler when there's no > >>>> hotplug interrupt available. > >>> > >>> Is there a simple way to do that? I'm not seeing any references to > >>> scrambling in the current driver. > >>> > >>> Should I just limit the rate to HDMI14_MAX_TMDSCLK (340000000) under > >>> dw_hdmi_qp_bridge_tmds_char_rate_valid() if using EDID polling? A > >>> document I found online from Synopsys [1] claims that scrambling is > >>> used by default at rates above 340 (if I'm reading it right) and used > >>> opportunistically at rates below 340. > >> > >> Yep, that's what you should be testing for :) > >> > >> Maxime > > > > Thanks, though now that I dig into it I'm a bit more confused on the > > best way forward. It looks like for today the driver is hard-limited > > to HDMI14_MAX_TMDSCLK because scrambling isn't supported. I'm assuming > > it will be at some point, suggesting that we *will* need this in the > > future. Is it sufficient to just add a comment there noting we need > > to check, or should I add a check there (that does nothing today) > > to ensure when we do support faster rates we are ready? > > I plan to work on upstreaming the scrambling support soon. Adding a TODO > comment would be enough for me to take care of the rest, but I'll still need > your help to get that tested, though. :-) > > Cristian
Okay, I'll add a TODO there to make sure that we put in special handling for when we have scrambling enabled, then when you have patches ready I can test it. Thank you, Chris
