Re: [PATCH v7 0/8] Add support for handling PCIe M.2 Key E connectors in devicetree

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

On Tue, Apr 14, 2026 at 01:03:19PM +0800, Chen-Yu Tsai wrote:
> On Tue, Apr 14, 2026 at 12:08 AM Manivannan Sadhasivam <mani@kernel.org> wrote:
> > On Mon, Apr 13, 2026 at 07:33:12PM +0530, Manivannan Sadhasivam wrote:
> > > On Mon, Apr 13, 2026 at 03:54:59PM +0800, Chen-Yu Tsai wrote:
> > > > On Thu, Mar 26, 2026 at 01:36:28PM +0530, Manivannan Sadhasivam wrote:

...

> > > > - Given that this connector actually represents two devices, how do I
> > > >   say I want the BT part to be a wakeup source, but not the WiFi part?
> > > >   Does wakeup-source even work at this point?
> > >
> > > You can't use the DT property since the devices are not described in DT
> > > statically. But you can still use the per-device 'wakeup' sysfs knob to enable
> > > wakeup.
> 
> I see. I think not being able to specify generic properties for the devices
> on the connector is going to be a bit problematic.

This is nature of the open-connectors, especially on the busses that are
hotpluggable, like PCIe. We never know what is connected there _ahead_.

In other words you can't describe in DT something that may not exist.

> requires specifying a bounce buffer / SWIOTLB for the PCIe WiFi card. The
> PCIe controller does not have an IOMMU behind it.

-- 
With Best Regards,
Andy Shevchenko