From: Kenji Kaneshige Date: Mon, 11 Jul 2011 01:15:45 +0000 (+0900) Subject: PCI: pciehp: change wait time for valid configuration access X-Git-Tag: firefly_0821_release~3680^2~4814^2~4 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=0cab0841dc1400f633a7e1ac1e448518692f927a;p=firefly-linux-kernel-4.4.55.git PCI: pciehp: change wait time for valid configuration access Naoki Yanagimoto reported that configuration read on some hot-added PCIe device returns invalid value. This patch fixes this problem. According to the PCIe spec, software must wait for at least 1 second to judge if the hot-added device is broken after Data Link Layer State Changed Event. This patch changes pciehp driver to wait for 1 second after the Data Link Layer State Changed Event is detected before initiating a configuration access instead of 100 ms. Signed-off-by: Kenji Kaneshige Tested-by: Naoki Yanagimoto Signed-off-by: Jesse Barnes --- diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c index 085dbb5fc168..1e9c9aacc3a6 100644 --- a/drivers/pci/hotplug/pciehp_ctrl.c +++ b/drivers/pci/hotplug/pciehp_ctrl.c @@ -213,6 +213,9 @@ static int board_added(struct slot *p_slot) goto err_exit; } + /* Wait for 1 second after checking link training status */ + msleep(1000); + /* Check for a power fault */ if (ctrl->power_fault_detected || pciehp_query_power_fault(p_slot)) { ctrl_err(ctrl, "Power fault on slot %s\n", slot_name(p_slot)); diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 50a23da5d24d..96dc4734e4af 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -275,16 +275,9 @@ int pciehp_check_link_status(struct controller *ctrl) * hot-plug capable downstream port. But old controller might * not implement it. In this case, we wait for 1000 ms. */ - if (ctrl->link_active_reporting){ - /* Wait for Data Link Layer Link Active bit to be set */ + if (ctrl->link_active_reporting) pcie_wait_link_active(ctrl); - /* - * We must wait for 100 ms after the Data Link Layer - * Link Active bit reads 1b before initiating a - * configuration access to the hot added device. - */ - msleep(100); - } else + else msleep(1000); retval = pciehp_readw(ctrl, PCI_EXP_LNKSTA, &lnk_status);