From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rajat Jain Date: Tue, 05 Nov 2013 22:33:28 +0000 Subject: [PATCH] pciehp: Acknowledge the spurious "cmd completed" event. Message-Id: <52797238.8070304@gmail.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-pci@vger.kernel.org, linux-hotplug@vger.kernel.org, Bjorn Helgaas , Kenji Kaneshige , Yijing Wang Cc: Guenter Roeck , Rajat Jain , Greg KH , Tom Nguyen , Kristen Accardi , Rajat Jain In case of a spurious "cmd completed", pcie_write_cmd() does not clear it, but yet expects more "cmd completed" events to be generated. This does not happen because the previous (spurious) event has not been acknowledged. Fix that. Signed-off-by: Rajat Jain Signed-off-by: Guenter Roeck --- This is how I saw it in action: my controller does not implement any hot-plug elements (LED, power ctrl, EMI etc) but still supports Command completed bit. - During initialization, pcie_disable_notification() -> pcie_write_cmd() -> writes to Slot control register -> which causes PCI_EXP_SLTSTA_CC to get set, which is not cleared, because IRQ is not generated (we just disabled notifications). - After some time, pcie_enable_notification() -> pcie_write_cmd() -> finds PCI_EXP_SLTSTA_CC is set, assumes it is spurious. -> Does not clear it, yet expects more command completed events to be generated (never happens). drivers/pci/hotplug/pciehp_hpc.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 5b8d749..ba8e06f 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -185,6 +185,7 @@ static int pcie_write_cmd(struct controller *ctrl, u16 cmd, u16 mask) } if (slot_status & PCI_EXP_SLTSTA_CC) { + pciehp_writew(ctrl, PCI_EXP_SLTSTA, PCI_EXP_SLTSTA_CC); if (!ctrl->no_cmd_complete) { /* * After 1 sec and CMD_COMPLETED still not set, just -- 1.7.9.5