Re: [PATCH] PCI/shpchp: fix a bus speed issue on hotplug

From: Marcel Apfelbaum
Date: Sun May 04 2014 - 06:40:52 EST


On Thu, 2014-05-01 at 14:00 -0600, Bjorn Helgaas wrote:
> On Thu, May 1, 2014 at 12:57 PM, Marcel Apfelbaum
> <marcel.apfelbaum@xxxxxxxxx> wrote:
> > On Thu, 2014-05-01 at 21:13 +0300, Marcel Apfelbaum wrote:
> >> On Thu, 2014-05-01 at 12:02 -0600, Bjorn Helgaas wrote:
> >> > On Thu, May 1, 2014 at 8:35 AM, Marcel Apfelbaum <marcel.a@xxxxxxxxxx> wrote:
> >> > > When a board is added, the shpchp driver checks if there
> >> > > is a mismatch between the bridge's adapter and the bus speed.
> >> > > If there is, it sets the subordinate speed (if there is no device on it).
> >> > >
> >> > > However, it takes the reference of the board speed from the primary bus
> >> > > and not from the subordinate. If the primary bus is PCI and not PCIX/PCIe,
> >> > > its speed is not updated and remains 0xff. As a result hotplug fails
> >> > > with error: "Speed of bus ff and adapter 0 mismatch".
> >> >
> >> > It'd be cool to have a bugzilla for this with lspci and dmesg output.
> >> > I'll also have to check the other hotplug drivers for similar issues,
> >> > unless you've already done that.
> >> I'll open a BZ with the details, sure.
> > Done: https://bugzilla.kernel.org/show_bug.cgi?id=75251
> > If you need further details, please let me know.
>
> Thanks. Would you mind attaching the "lspci -vv" output? That should
> show more details, including the information used to compute the bus
> speed.
>
> Also, you checked the "regression" box. Can you confirm that and
> identify a known-working kernel? If we know which kernels are broken,
> we can potentially mark the fix to be backported to them.
I checked 2.6.24-26-generic that comes with Ubuntu 8.04 and it works OK.
So we have a working version.

I hope it helps,
Marcel

>
> Bjorn



--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/