0b496b19ab
commit c9260693aa0c1e029ed23693cfd4d7814eee6624 upstream.
Commit ac91e6980563 ("PCI: Unify delay handling for reset and resume")
shortened an unconditional 1 sec delay after a Secondary Bus Reset to 100
msec for PCIe (per PCIe r6.1 sec 6.6.1). The 1 sec delay is only required
for Conventional PCI.
But it turns out that there are PCIe devices which require a longer delay
than prescribed before first config space access after reset recovery or
resume from D3cold:
Chad reports that a "VideoPropulsion Torrent QN16e" MPEG QAM Modulator
"raises a PCI system error (PERR), as reported by the IPMI event log, and
the hardware itself would suffer a catastrophic event, cycling the server"
unless the longer delay is observed.
The card is specified to conform to PCIe r1.0 and indeed only supports Gen1
speed (2.5 GT/s) according to lspci. PCIe r1.0 sec 7.6 prescribes the same
100 msec delay as PCIe r6.1 sec 6.6.1:
To allow components to perform internal initialization, system software
must wait for at least 100 ms from the end of a reset (cold/warm/hot)
before it is permitted to issue Configuration Requests
The behavior of the Torrent QN16e card thus appears to be a quirk. Treat
it as such and lengthen the reset delay for this specific device.
Fixes: ac91e6980563 ("PCI: Unify delay handling for reset and resume")
Link: https://lore.kernel.org/r/47727e792c7f0282dc144e3ec8ce8eb6e713394e.1695304512.git.lukas@wunner.de
Reported-by: Chad Schroeder <CSchroeder@sonifi.com>
Closes: https://lore.kernel.org/linux-pci/DM6PR16MB2844903E34CAB910082DF019B1FAA@DM6PR16MB2844.namprd16.prod.outlook.com/
Tested-by: Chad Schroeder <CSchroeder@sonifi.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.