On Thu, Apr 23, 2020 at 09:02:02PM +0200, Pali Rohár wrote:
> On Thursday 23 April 2020 13:41:51 Bjorn Helgaas wrote:
> > [+cc Rob]
> >
> > On Tue, Apr 21, 2020 at 01:16:56PM +0200, Marek Behún wrote:
> > > From: Pali Rohár <pali@xxxxxxxxxx>
> > >
> > > Add support for issuing PERST via GPIO specified in 'reset-gpios'
> > > property (as described in PCI device tree bindings).
> > >
> > > Some buggy cards (e.g. Compex WLE900VX or WLE1216) are not detected
> > > after reboot when PERST is not issued during driver initialization.
> >
> > Does this slot support hotplug?
>
> I have no idea. I have not heard that anybody tried hotplugging cards
> with this aardvark pcie controller at runtime.
>
> This patch fixes initialization only at boot time when cards were
> plugged prior powering board on.
>
> > If so, I don't think this fix will help the hot-add case, will it?
>
> I even do not know if aardvark HW supports it. And if yes, I think it is
> unimplemented and/or broken.
>
> In documentation there is some interrupt register which could signal it,
> but I it is not used by kernel's pci-aardvark.c driver.
"lspci -vv" will show you whether the hardware claims to support it,
e.g.,
00:1c.0 PCI bridge: Intel Corporation Sunrise Point-LP PCI Express Root Port #1
Capabilities: [40] Express (v2) Root Port (Slot+), MSI 00
SltCap: AttnBtn- PwrCtrl- MRL- AttnInd- PwrInd- HotPlug- Surprise-
If the right combination of bits are set there, pciehp will claim the
port and support hotplug.
Bjorn
