Re: [PATCH] usb: typec: ucsi: introduce read_explicit operation

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

Hi Sam,

On Sat, Apr 01, 2023 at 08:06:57PM +0200, Samuel Čavoj wrote:
> > 
> > Okay... Did you see those errors with your original patch?
> 
> I'm pretty sure that it's the same, yeah. The specific error is
> one (or a seemingly random sequence) of the following:
> 
> - con2: failed to register partner alt modes (-22)
> - con2: failed to register partner alt modes (-5)
> - GET_CURRENT_CAM command failed (also caused by a -22 from exec_command)
> 
> Doesn't occur with nothing or only a charger plugged in. Once I plug
> a USB-C to DP adapter or a cheap USB-C hub (with an internal DP->HDMI
> converter, USB3 hub and GbE in one of the hub ports), the errors
> randomly show up when reloading the module or when plugging in once
> already loaded. Not consistent at all.
> 
> So seems to be alt-mode related. Will probably need some more
> investigation on my part, unless you've got any ideas off the
> bat.

The alt mode stuff is very annoying with UCSI. I think Windows is only
interested in the connector alt modes. With the partner alt modes the
responses differ on almost every system, and several platforms
actually never return anything when you request the partner alt modes
with GET_ALTERNATE_MODES.

But I think we can move forward with this fix. I'll send it tomorrow.

Br,

-- 
heikki