From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Niklas Cassel <niklas.cassel@linaro.org>
Cc: Stanimir Varbanov <svarbanov@mm-sol.com>,
Marc Zyngier <marc.zyngier@arm.com>,
linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
Trent Piepho <tpiepho@impinj.com>,
Jingoo Han <jingoohan1@gmail.com>,
Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
faiz_abbas@ti.com, Joao Pinto <Joao.Pinto@synopsys.com>,
Vignesh R <vigneshr@ti.com>
Subject: Re: [PATCH 0/3] PCI: designware: Fixing MSI handling flow
Date: Mon, 3 Dec 2018 17:42:57 +0000 [thread overview]
Message-ID: <20181203174257.GA13670@e107981-ln.cambridge.arm.com> (raw)
In-Reply-To: <20181203130924.GA5105@centauri.lan>
On Mon, Dec 03, 2018 at 02:09:24PM +0100, Niklas Cassel wrote:
> On Mon, Dec 03, 2018 at 10:42:19AM +0000, Lorenzo Pieralisi wrote:
> > On Sun, Dec 02, 2018 at 12:50:58AM +0100, Niklas Cassel wrote:
> > > On Wed, Nov 21, 2018 at 07:24:53PM +0200, Stanimir Varbanov wrote:
> > > > Hi,
> > > >
> > > > On 11/14/18 12:57 AM, Marc Zyngier wrote:
> > > > > It recently came to light that the Designware PCIe driver is rather
> > > > > broken in the way it handles MSI[1]:
> > > > >
> > > > > - It masks interrupt by disabling them, meaning that MSIs generated
> > > > > during the masked window are simply lost. Oops.
> > > > >
> > > > > - Acking of the currently pending MSI is done outside of the interrupt
> > > > > flow, getting moved around randomly and ultimately breaking the
> > > > > driver. Not great.
> > > > >
> > > > > This series attempts to address this by switching to using the MASK
> > > > > register for masking interrupts (!), and move the ack into the
> > > > > appropriate callback, giving it a fixed place in the MSI handling
> > > > > flow.
> > > > >
> > > > > Note that this is only compile-tested on my arm64 laptop, as I'm
> > > > > travelling and do not have the required HW to test it anyway. I'd
> > > > > welcome both review and testing by the interested parties (dwc
> > > > > maintainer and users affected by existing bugs).
> > > > >
> > > > > Thanks,
> > > > >
> > > > > M.
> > > > >
> > > > > [1] https://patchwork.kernel.org/patch/10657987/
> > > > >
> > > > > Marc Zyngier (3):
> > > > > PCI: designware: Use interrupt masking instead of disabling
> > > > > PCI: designware: Take lock when ACKing an interrupt
> > > > > PCI: designware: Move interrupt acking into the proper callback
> > > > >
> > > > > .../pci/controller/dwc/pcie-designware-host.c | 22 ++++++++++++-------
> > > > > 1 file changed, 14 insertions(+), 8 deletions(-)
> > > > >
> > > >
> > > > for pcie-qcom:
> > > >
> > > > Tested-by: Stanimir Varbanov <svarbanov@mm-sol.com>
> > >
> > > Hello PCI folks,
> > >
> > > Since this is a real bug, we should try get a couple of Tested-by tags
> > > before it's too late.
> > > It would be nice if v4.20 was released without broken MSIs in this driver.
> > >
> > > Personally I get confused just by looking at this mail thread.
> > >
> > > I see 3 patches from Marc and a fix-up from Marc, but I also see
> > > a patch from Gustavo, and another patch from Trent.
> > >
> > > Is seems like Lorenzo has a branch with Marc's 3 patches + Marc's fix-up
> > > folded in here:
> > > https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/log/?h=test%2Fpci-dwc-msi
> > >
> > > Perhaps it would be a good idea to send a V2, with proper Fixes-tags,
> > > just so that people would know what to test, so that we can start getting
> > > those Tested-by tags.
> >
> > Perhaps it would be a good idea to pull the branch above and test it
> > after I have sent three reminders to all DWC host bridge maintainers through
> > this email thread.
> >
> > I have no problem reposting those patches but it is time you started
> > testing them, I have already explained what's the issue they are fixing
> > in this thread, I do not think a Fixes: tag will add any further degree
> > of urgency.
> >
>
> I tested Lorenzo's
> https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/log/?h=test%2Fpci-dwc-msi
> branch with drivers/pci/controller/dwc/pcie-qcom.c.
>
> Without this branch, when having an ath10k PCIe endpoint connected,
> and simply running the ath10k as a host access point (running hostapd):
> watch cat /proc/interrupts | grep ath10k_pci
> I consistenly stop getting interrupts in less than a minute.
>
> With this branch, I've been able to run the same test case successfully
> for 30+ minutes.
>
> Tested-by: Niklas Cassel <niklas.cassel@linaro.org>
Thank you very much, I need this tag on linux-pci@vger.kernel.org in
reply to this series:
https://patchwork.ozlabs.org/project/linux-pci/list/?series=75827
I need more testing done, I encourage other DWC maintainers to test my
branch above. I am mulling over it but I may consider this v4.21
material if I do not get enough testing done this week.
Thanks,
Lorenzo
next prev parent reply other threads:[~2018-12-03 17:43 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-13 22:57 [PATCH 0/3] PCI: designware: Fixing MSI handling flow Marc Zyngier
2018-11-13 22:57 ` [PATCH 1/3] PCI: designware: Use interrupt masking instead of disabling Marc Zyngier
2018-12-03 18:02 ` [1/3] " Niklas Cassel
2018-12-04 9:41 ` [PATCH 1/3] " Gustavo Pimentel
2018-11-13 22:57 ` [PATCH 2/3] PCI: designware: Take lock when ACKing an interrupt Marc Zyngier
2018-11-14 19:08 ` Trent Piepho
2018-12-03 18:02 ` [2/3] " Niklas Cassel
2018-12-04 9:41 ` [PATCH 2/3] " Gustavo Pimentel
2018-11-13 22:57 ` [PATCH 3/3] PCI: designware: Move interrupt acking into the proper callback Marc Zyngier
2018-11-14 19:01 ` Trent Piepho
2018-12-03 18:02 ` [3/3] " Niklas Cassel
2018-12-04 9:41 ` [PATCH 3/3] " Gustavo Pimentel
2018-12-04 10:20 ` Kishon Vijay Abraham I
2018-12-04 13:45 ` Marc Zyngier
2018-12-07 8:12 ` Kishon Vijay Abraham I
2018-12-07 9:45 ` Marc Zyngier
2018-12-07 10:13 ` Kishon Vijay Abraham I
2018-12-11 12:35 ` Lorenzo Pieralisi
2018-12-12 5:54 ` Kishon Vijay Abraham I
2018-11-13 23:16 ` [PATCH 0/3] PCI: designware: Fixing MSI handling flow Gustavo Pimentel
2018-11-14 9:54 ` Marc Zyngier
2018-11-14 19:19 ` Trent Piepho
2018-11-14 22:01 ` Marc Zyngier
2018-11-14 22:25 ` Trent Piepho
2018-11-14 22:44 ` Marc Zyngier
2018-11-14 23:23 ` Trent Piepho
2018-11-19 20:37 ` Trent Piepho
2018-11-22 12:03 ` Gustavo Pimentel
2018-11-22 16:07 ` Gustavo Pimentel
2018-11-22 16:26 ` Lorenzo Pieralisi
2018-11-22 16:38 ` Marc Zyngier
2018-11-22 17:40 ` Gustavo Pimentel
2018-11-26 16:06 ` Trent Piepho
2018-11-27 7:51 ` Marc Zyngier
2018-11-27 17:23 ` Trent Piepho
2018-11-22 17:49 ` Gustavo Pimentel
2018-11-26 15:52 ` Trent Piepho
2018-11-27 7:50 ` Marc Zyngier
2018-11-27 18:12 ` Trent Piepho
2018-12-07 16:16 ` Gustavo Pimentel
2018-11-14 18:28 ` Trent Piepho
2018-11-14 22:07 ` Marc Zyngier
2018-11-14 22:50 ` Trent Piepho
2018-11-15 15:22 ` Gustavo Pimentel
2018-11-15 18:37 ` Trent Piepho
2018-11-15 19:29 ` Marc Zyngier
2018-11-19 20:14 ` Trent Piepho
2018-11-21 17:24 ` Stanimir Varbanov
2018-12-01 23:50 ` Niklas Cassel
2018-12-02 11:28 ` Stanimir Varbanov
2018-12-03 10:42 ` Lorenzo Pieralisi
2018-12-03 13:09 ` Niklas Cassel
2018-12-03 17:42 ` Lorenzo Pieralisi [this message]
2018-12-03 20:31 ` Trent Piepho
2018-12-10 16:17 ` Lorenzo Pieralisi
2018-12-10 16:30 ` Marc Zyngier
2018-12-10 18:15 ` Trent Piepho
2018-12-10 18:31 ` Marc Zyngier
2018-12-10 20:34 ` Trent Piepho
2018-12-12 9:10 ` Gustavo Pimentel
2018-12-12 8:55 ` Gustavo Pimentel
2018-12-11 11:43 ` Lorenzo Pieralisi
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