From mboxrd@z Thu Jan  1 00:00:00 1970
From: arno@natisbad.org (Arnaud Ebalard)
Date: Tue, 18 Feb 2014 21:54:31 +0100
Subject: [BUG] FL1009: xHCI host not responding to stop endpoint command.
References: <87eh4dot61.fsf@natisbad.org> <87sissopaf.fsf@natisbad.org>
 <20140114170719.GA12126@xanatos> <87bnzekz5l.fsf@natisbad.org>
 <063D6719AE5E284EB5DD2968C1650D6D45C5AB@AcuExch.aculab.com>
 <87mwix5anm.fsf@natisbad.org> <20140116185044.GC18392@xanatos>
 <87fvon2khn.fsf@natisbad.org> <87zjmvau23.fsf@nemi.mork.no>
 <20140117205432.GB5618@xanatos> <87vbxhrmea.fsf@natisbad.org>
 <20140218141031.255bd1ba@skate>
Message-ID: <87ppmk2lbs.fsf@natisbad.org>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hi Thomas,

Thomas Petazzoni <thomas.petazzoni@free-electrons.com> writes:

> Dear Arnaud Ebalard,
>
> On Sat, 18 Jan 2014 22:49:17 +0100, Arnaud Ebalard wrote:
>
>> I started suspecting the introduction of MSI support in Marvell PCIe
>> host controller driver (FL1009 is on the PCIe bus) and compiled a
>> a 3.13.0-rc8 w/ CONFIG_PCI_MSI disabled (it was enabled in all my
>> previous tests): I did not manage to reproduce the issue with this
>> kernel. As a side note, commits 5b4deb6526bd, 31f614edb726 and
>> 627dfcc249e2 are
>> 
>> ATM, I do not know if the problem is related to a bug in introduced MSI
>> support or some weird incompatibility of that functionality with the
>> FL1009 which would require some quirk in XHCI stack.
>> 
>> Thomas, I took a look at the changes but I am not familiar w/ how MSI
>> work. You may have an idea on what is going on here.
>
> I finally got some idea: your kernel 3.13-rc7 lacks a very important
> fix we did in the irqchip driver MSI handling. You really need to have
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/drivers/irqchip/irq-armada-370-xp.c?id=c7f7bd4a136e4b02dd2a66bf95aec545bd93e8db
> applied to get proper MSI behavior. Without this patch, there is a race
> condition, and some MSI interrupts might be lost.
>
> This commit was merged in v3.14-rc2, and backported to 3.13 and
> previous stable releases.
>
> Can you test after applying this commit?

Just to be sure, I compiled a 3.13 w/ PCI_MSI enabled and w/o the fix:
it failed as usual. Then, I just applied the fix on top of it and tested
again: I was unable to make it fail, i.e. this oneline fixes the issue.

Sarah, I guess this also validates the fact that FL1009 has good MSI
support ;-)

Thanks for the time you both spent. Let's close the case.

Cheers,

a+