PCIe recovery mechanism

PCIe recovery mechanism

[Avinash Patil]

Hello,

I was wondering if there is any way to recover from FW crash in case
of WLAN PCie cards- say we power off card and power on. This would
enable hotplug to detect it again and driver's probe routine would do
redownload of FW and device is alive again.

1. I went through PCI bus driver sources and came across
pci_set_power_state which can be used to set PCI power state to
D0-D3hot/D3cold. Suppose we set power state to D3Cold, I dont think
dev pointer would be valid again to set to D0.

2. Another idea is something similar to PCI rescan operation via
sysfs(echo 1 > /sys/bus/pci/rescan). I am not entirely sure though if
this can be applied to single device as this involves scanning all
devices on PCI bus.

Any help appreciated!

Thanks,
Avinash

PCIe recovery mechanism

[Greg KH]

On Fri, Jan 09, 2015 at 10:19:15AM +0530, Avinash Patil wrote:
> Hello,
> 
> I was wondering if there is any way to recover from FW crash in case
> of WLAN PCie cards- say we power off card and power on. This would
> enable hotplug to detect it again and driver's probe routine would do
> redownload of FW and device is alive again.

You can't power-down a pci card unless you have special hardware that
controls the power, like a pci hotplug controller.  Those are not very
common.

good luck,

greg k-h