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| author |   Liguang Zhang <zhangliguang@linux.alibaba.com> | 2021-11-11 13:42:58 +0800 |
|---|---|---|
| committer |   Bjorn Helgaas <bhelgaas@google.com> | 2022-02-03 13:36:23 -0600 |
| commit | 92912b175178c7e895f5e5e9f1e30ac30319162b (patch) | |
| tree | de538075a66681ea2fb7c831d4de8f506a9db4f0 /drivers/pci/hotplug/pciehp_hpc.c | |
| parent | Linux 5.17-rc1 (diff) | |
| download | linux-dev-92912b175178c7e895f5e5e9f1e30ac30319162b.tar.xz linux-dev-92912b175178c7e895f5e5e9f1e30ac30319162b.zip | |
PCI: pciehp: Clear cmd_busy bit in polling mode
Writes to a Downstream Port's Slot Control register are PCIe hotplug
"commands." If the Port supports Command Completed events, software must
wait for a command to complete before writing to Slot Control again.
pcie_do_write_cmd() sets ctrl->cmd_busy when it writes to Slot Control. If
software notification is enabled, i.e., PCI_EXP_SLTCTL_HPIE and
PCI_EXP_SLTCTL_CCIE are set, ctrl->cmd_busy is cleared by pciehp_isr().
But when software notification is disabled, as it is when pcie_init()
powers off an empty slot, pcie_wait_cmd() uses pcie_poll_cmd() to poll for
command completion, and it neglects to clear ctrl->cmd_busy, which leads to
spurious timeouts:
pcieport 0000:00:03.0: pciehp: Timeout on hotplug command 0x01c0 (issued 2264 msec ago)
pcieport 0000:00:03.0: pciehp: Timeout on hotplug command 0x05c0 (issued 2288 msec ago)
Clear ctrl->cmd_busy in pcie_poll_cmd() when it detects a Command Completed
event (PCI_EXP_SLTSTA_CC).
[bhelgaas: commit log]
Fixes: a5dd4b4b0570 ("PCI: pciehp: Wait for hotplug command completion where necessary")
Link: https://lore.kernel.org/r/20211111054258.7309-1-zhangliguang@linux.alibaba.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215143
Link: https://lore.kernel.org/r/20211126173309.GA12255@wunner.de
Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org # v4.19+
Diffstat (limited to 'drivers/pci/hotplug/pciehp_hpc.c')
| -rw-r--r-- | drivers/pci/hotplug/pciehp_hpc.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 1c1ebf3dad43..85dce560831a 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -98,6 +98,8 @@ static int pcie_poll_cmd(struct controller *ctrl, int timeout) if (slot_status & PCI_EXP_SLTSTA_CC) { pcie_capability_write_word(pdev, PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_CC); + ctrl->cmd_busy = 0; + smp_mb(); return 1; } msleep(10); |