6.6-stable review patch. If anyone has any objections, please let me know.
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From: Lukas Wunner lukas@wunner.de
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.169530451... Reported-by: Chad Schroeder CSchroeder@sonifi.com Closes: https://lore.kernel.org/linux-pci/DM6PR16MB2844903E34CAB910082DF019B1FAA@DM6... 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 --- drivers/pci/quirks.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
--- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -6211,3 +6211,15 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_I DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_XILINX, 0x5020, of_pci_make_dev_node); DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_XILINX, 0x5021, of_pci_make_dev_node); DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_REDHAT, 0x0005, of_pci_make_dev_node); + +/* + * Devices known to require a longer delay before first config space access + * after reset recovery or resume from D3cold: + * + * VideoPropulsion (aka Genroco) Torrent QN16e MPEG QAM Modulator + */ +static void pci_fixup_d3cold_delay_1sec(struct pci_dev *pdev) +{ + pdev->d3cold_delay = 1000; +} +DECLARE_PCI_FIXUP_FINAL(0x5555, 0x0004, pci_fixup_d3cold_delay_1sec);