From: "Spassov, Stanislav" <stanspas@amazon.de>
To: "helgaas@kernel.org" <helgaas@kernel.org>
Cc: "alex.williamson@redhat.com" <alex.williamson@redhat.com>,
"ashok.raj@intel.com" <ashok.raj@intel.com>,
"okaya@kernel.org" <okaya@kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"Wang, Wei" <wawei@amazon.de>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"Schoenherr, Jan H." <jschoenh@amazon.de>,
"rajatja@google.com" <rajatja@google.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: Re: [PATCH 2/3] PCI: Introduce per-device reset_ready_poll override
Date: Mon, 24 Feb 2020 18:05:02 +0000 [thread overview]
Message-ID: <52543631a871ba576b9711d5b6a3fad12019cece.camel@amazon.de> (raw)
In-Reply-To: <20200224143450.GA219843@google.com>
On Mon, 2020-02-24 at 08:34 -0600, Bjorn Helgaas wrote:
> I like the factoring out of the timeout, since all callers of
> pci_dev_wait() supply the same value. That could be its own separate
> preliminary patch...
Agreed. The next version of this patch series will do the refactor separately.
I am thinking we might also want to replace the "reset_type" with an enum
that indexes into an array to get the string, but -- more importantly --
indexes into an array of per-device overrides for the various reset types.
As per discussion on PATCH 1, I noticed the ACPI _DSM method detailed in
PCI Firmware Spec r3.2, 4.6.9 can provide individual delay values for five
different scenarios (Conventional Reset, DL_Up, FLR, D3hot to D0, VF Enable),
so we should probably store each of them in struct pci_dev.
> I'm a little wary of "lowering the global default post-reset timeout"
> because that's not safe in general. For example, a hot-added device
> that is completely spec compliant regarding post-reset timing may not
> work correctly if we've lowered a global timeout.
>
That makes sense. However, the timeout is currently 1 minute.
The only user of this value is pci_dev_wait(), which is itself
only invoked as part of various resets. Are there any scenarios
where that much time is truly needed after a device reset?
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next prev parent reply other threads:[~2020-02-24 18:05 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-23 12:20 [PATCH 0/3] Improve PCI device post-reset readiness polling Stanislav Spassov
2020-02-23 12:20 ` [PATCH 1/3] PCI: Make PCIE_RESET_READY_POLL_MS configurable Stanislav Spassov
2020-02-24 14:15 ` Bjorn Helgaas
2020-02-24 17:52 ` Spassov, Stanislav
2020-02-27 21:45 ` Bjorn Helgaas
2020-02-27 23:44 ` Sinan Kaya
2020-02-28 2:18 ` Raj, Ashok
2020-03-02 16:39 ` Sinan Kaya
2020-03-02 17:37 ` Raj, Ashok
2020-03-02 18:30 ` Sinan Kaya
2020-02-23 12:20 ` [PATCH 2/3] PCI: Introduce per-device reset_ready_poll override Stanislav Spassov
2020-02-24 14:34 ` Bjorn Helgaas
2020-02-24 18:05 ` Spassov, Stanislav [this message]
2020-02-23 12:20 ` [PATCH 3/3] PCI: Add CRS handling to pci_dev_wait() Stanislav Spassov
2020-02-24 20:41 ` Bjorn Helgaas
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