Re: USB-C DisplayPort display failing to stay active with Intel Barlow Ridge USB4 controller, power-management related issue?

[Mika Westerberg <mika.westerberg@linux.intel.com>]

Hi,

On Thu, Nov 07, 2024 at 11:45:44AM +0200, Mika Westerberg wrote:
> Hi,
> 
> On Wed, Nov 06, 2024 at 11:01:34AM -0600, Aaron Rainbolt wrote:
> > > Unfortunately that does not help here. I need to figure something else
> > > how to detect the redrive case with this firmware but first, does this
> > > work in Windows? I mean if you install Windows to this same system
> > > does it work as expected?
> > 
> > It does work as expected under Windows 11, with one major caveat. We
> > used a Windows 11 ISO with a setup.exe created on April 05 2023 for
> > installing the test system, and after initial installation it behaved
> > exactly the same way as Linux behaves now (displays going blank soon
> > after being plugged in). However, after installing all available
> > Windows updates, the issue resolved, and the displays worked exactly as
> > intended (the screens are recognized when attached and do not end up
> > disconnecting after a timeout).
> > 
> > Would it be helpful to test on Windows 11, and provide a report and
> > system logs?
> 
> Unfortunately, I don't know anything about Windows ;-)
> 
> However, I asked our Thunderbolt hardware/firmware team about this, if
> they have any idea how it was solved in Windows side. Might take a
> couple of days though.

While waiting for this, I wonder if you guys could do one more
experiment? I would like to get the traces what is happening there
(hoping something pops out there). Following steps:

  1. Download and install tbtools [1].
  2. Build and install the kernel with my "redrive" patch.
  3. Boot the system up, nothing connected.
  4. Wait until the Barlow Ridge is in runtime suspend (so wait for
     ~30s or so)
  5. Enable tracing:

    # tbtrace enable

  6. Plug in USB-C monitor to the USB-C port of the Barlow Ridge. Do not
     run 'lspci -k'. Expectation here is that there is no picture on
     the monitor (in other words the issue reproduces).

  7. Stop tracing and take full dump:

    # tbtrace disable
    # tbtrace dump -vv > trace.out

  8. Send trace.out along with full dmesg to me.

Thanks!

[1] https://github.com/intel/tbtools