From 99f0169c17f334a11b0ace91188501c612f3e1e6 Mon Sep 17 00:00:00 2001 From: Kenji Kaneshige Date: Tue, 3 Feb 2009 15:06:16 +0900 Subject: [PATCH] PCI: pciehp: enable software notification on empty slots Current pciehp disables software notification of adapter presence changed event and MRL changed event when slot is turned off. Because of this, there is no way to detect those events on empty slots in the current pciehp implementation. According to the past discussion(*), this behavior was introduced to prevent endless loop that could happen if pcie_isr() runs after power fault is detected on a certain platform whose stickey power-fault bit remains on till the slot is powered on again. (*) http://sourceforge.net/mailarchive/message.php?msg_id=20051130135409.A14918%40unix-os.sc.intel.com I think this endless loop can be avoided using one bit flag that indicates power fault had been detected, instead of disabling software notification of adapter present changed event and MRL changed event. With this patch, we can enable software notification mechanism of presence changed and MRL changed event on the empty slots again. Signed-off-by: Kenji Kaneshige Signed-off-by: Jesse Barnes --- drivers/pci/hotplug/pciehp.h | 1 + drivers/pci/hotplug/pciehp_hpc.c | 31 +++++++++++-------------------- 2 files changed, 12 insertions(+), 20 deletions(-) diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h index 1f887f64e493..2bf8d28062e8 100644 --- a/drivers/pci/hotplug/pciehp.h +++ b/drivers/pci/hotplug/pciehp.h @@ -112,6 +112,7 @@ struct controller { unsigned int no_cmd_complete:1; unsigned int link_active_reporting:1; unsigned int notification_enabled:1; + unsigned int power_fault_detected; }; #define INT_BUTTON_IGNORE 0 diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index c1a312f24060..07bd32151146 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -548,23 +548,21 @@ static int hpc_power_on_slot(struct slot * slot) slot_cmd = POWER_ON; cmd_mask = PCI_EXP_SLTCTL_PCC; - /* Enable detection that we turned off at slot power-off time */ if (!pciehp_poll_mode) { - slot_cmd |= (PCI_EXP_SLTCTL_PFDE | PCI_EXP_SLTCTL_MRLSCE | - PCI_EXP_SLTCTL_PDCE); - cmd_mask |= (PCI_EXP_SLTCTL_PFDE | PCI_EXP_SLTCTL_MRLSCE | - PCI_EXP_SLTCTL_PDCE); + /* Enable power fault detection turned off at power off time */ + slot_cmd |= PCI_EXP_SLTCTL_PFDE; + cmd_mask |= PCI_EXP_SLTCTL_PFDE; } retval = pcie_write_cmd(ctrl, slot_cmd, cmd_mask); - if (retval) { ctrl_err(ctrl, "Write %x command failed!\n", slot_cmd); - return -1; + return retval; } ctrl_dbg(ctrl, "%s: SLOTCTRL %x write cmd %x\n", __func__, ctrl->cap_base + PCI_EXP_SLTCTL, slot_cmd); + ctrl->power_fault_detected = 0; return retval; } @@ -621,18 +619,10 @@ static int hpc_power_off_slot(struct slot * slot) slot_cmd = POWER_OFF; cmd_mask = PCI_EXP_SLTCTL_PCC; - /* - * If we get MRL or presence detect interrupts now, the isr - * will notice the sticky power-fault bit too and issue power - * indicator change commands. This will lead to an endless loop - * of command completions, since the power-fault bit remains on - * till the slot is powered on again. - */ if (!pciehp_poll_mode) { - slot_cmd &= ~(PCI_EXP_SLTCTL_PFDE | PCI_EXP_SLTCTL_MRLSCE | - PCI_EXP_SLTCTL_PDCE); - cmd_mask |= (PCI_EXP_SLTCTL_PFDE | PCI_EXP_SLTCTL_MRLSCE | - PCI_EXP_SLTCTL_PDCE); + /* Disable power fault detection */ + slot_cmd &= ~PCI_EXP_SLTCTL_PFDE; + cmd_mask |= PCI_EXP_SLTCTL_PFDE; } retval = pcie_write_cmd(ctrl, slot_cmd, cmd_mask); @@ -710,9 +700,10 @@ static irqreturn_t pcie_isr(int irq, void *dev_id) pciehp_handle_presence_change(p_slot); /* Check Power Fault Detected */ - if (intr_loc & PCI_EXP_SLTSTA_PFD) + if ((intr_loc & PCI_EXP_SLTSTA_PFD) && !ctrl->power_fault_detected) { + ctrl->power_fault_detected = 1; pciehp_handle_power_fault(p_slot); - + } return IRQ_HANDLED; } -- 2.20.1