3.16.82-rc1 review patch. If anyone has any objections, please let me know.
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From: Jian-Hong Pan jian-hong@endlessm.com
commit e045fa29e89383c717e308609edd19d2fd29e1be upstream.
When a driver enables MSI-X, msix_program_entries() reads the MSI-X Vector Control register for each vector and saves it in desc->masked. Each register is 32 bits and bit 0 is the actual Mask bit.
When we restored these registers during resume, we previously set the Mask bit if *any* bit in desc->masked was set instead of when the Mask bit itself was set:
pci_restore_state pci_restore_msi_state __pci_restore_msix_state for_each_pci_msi_entry msix_mask_irq(entry, entry->masked) <-- entire u32 word __pci_msix_desc_mask_irq(desc, flag) mask_bits = desc->masked & ~PCI_MSIX_ENTRY_CTRL_MASKBIT if (flag) <-- testing entire u32, not just bit 0 mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT writel(mask_bits, desc_addr + PCI_MSIX_ENTRY_VECTOR_CTRL)
This means that after resume, MSI-X vectors were masked when they shouldn't be, which leads to timeouts like this:
nvme nvme0: I/O 978 QID 3 timeout, completion polled
On resume, set the Mask bit only when the saved Mask bit from suspend was set.
This should remove the need for 19ea025e1d28 ("nvme: Add quirk for Kingston NVME SSD running FW E8FK11.T").
[bhelgaas: commit log, move fix to __pci_msix_desc_mask_irq()] Link: https://bugzilla.kernel.org/show_bug.cgi?id=204887 Link: https://lore.kernel.org/r/20191008034238.2503-1-jian-hong@endlessm.com Fixes: f2440d9acbe8 ("PCI MSI: Refactor interrupt masking code") Signed-off-by: Jian-Hong Pan jian-hong@endlessm.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com [bwh: Backported to 3.16: adjust context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/pci/msi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -220,8 +220,9 @@ u32 default_msix_mask_irq(struct msi_des u32 mask_bits = desc->masked; unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE + PCI_MSIX_ENTRY_VECTOR_CTRL; + mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT; - if (flag) + if (flag & PCI_MSIX_ENTRY_CTRL_MASKBIT) mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT; writel(mask_bits, desc->mask_base + offset);