Messages in this thread | | | Subject | Re: [PATCH v7 3/3] PCI: Add tango MSI controller support | From | Marc Zyngier <> | Date | Wed, 14 Jun 2017 10:32:24 +0100 |
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On 14/06/17 10:19, Marc Gonzalez wrote: > On 14/06/2017 11:00, Marc Gonzalez wrote: > >> The MSI controller in Tango supports 256 message-signaled interrupts, >> and a single doorbell address. >> >> Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com> >> --- >> Changes from v6 to v7 >> o Call spin_lock() not spin_lock_irqsave() in the ISR >> --- >> drivers/pci/host/pcie-tango.c | 225 ++++++++++++++++++++++++++++++++++++++++++ >> 1 file changed, 225 insertions(+) > > Someone on IRC suggested testing the driver with LOCKDEP. > > If I understand the warning below correctly, I am not supposed > to call irq_domain_set_info() while holding used_msi_lock?
Indeed. This creates an AB/BA situation, which will eventually deadlock. Once again, lockdep saves the day.
> NB: in probe, my driver calls > > add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); > > This should not break LOCKDEP analysis, right?
It doesn't. The code is provably wrong, and lockdep proved that it is wrong.
M. -- Jazz is not dead. It just smells funny...
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