RE: [PATCH] drm/bridge: adv7511: Clear HPD IRQ before powering on device during resume()

[Biju Das]

Hi Laurent,

> -----Original Message-----
> From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> Sent: 17 March 2026 23:30
> Subject: Re: [PATCH] drm/bridge: adv7511: Clear HPD IRQ before powering on device during resume()
> 
> On Mon, Mar 16, 2026 at 05:59:57PM +0000, Biju Das wrote:
> > On 16 March 2026 14:03, Laurent Pinchart wrote:
> > > On Fri, Dec 19, 2025 at 10:46:53AM +0000, Biju wrote:
> > > > From: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > > >
> > > > On RZ/G3E SMARC EVK using PSCI, s2ram powers down the SoC. Testing
> > > > ADV7535 IRQ configured as edge-triggered interrupt on RZ/G3E SMARC
> > > > EVK shows that it is missing HPD IRQ during system resume, as the
> > > > status change occurs before the IRQ/pincontrol resume. Once the
> > > > status bit is set, there won't be any further IRQ unless the status bit is cleared.
> > > >
> > > > Clear any pending HPD IRQs before powering on the ADV7535 device
> > > > to deliver HPD interrupts after resume().
> > >
> > > This issue doesn't seem to be specific to the ADV7511. Any device
> > > that uses an edge-triggered interrupt could suffer from the same problem.
> > > Implementing a work around in the driver doesn't seem to be a solution that would scale.
> >
> > I don't see any bridge device is complaining about similar issues in Linux kernel.
> 
> This is exactly why this patch concerns me. The issue doesn't seem to be specific to the ADV7511, yet
> no other bridge driver implements anything similar. It seems to indicate something else is wrong.
> 
> I understand and agree with the analysis of the issue (although I find it weird that the interrupt
> controller or pin controller would be resumed after the ADV7511), but any device with an edge-
> triggered interrupt should then suffer from the same problem. This means it shouldn't be handled at
> individual drivers level, unless there's something I'm missing that makes the problem very specific to
> the ADV7511. Otherwise, a more generic solution is needed.

ADV7535 is special device, hardware reset automatically set the status bit, if a connector is
connected without software is turning power on unlike other devices.

Do you know any other bridge device shows this issue? i.e., without software turning the power on,
bridge device sets the status bit during power on reset??

Cheers,
Biju