From 3e82a7f9031f204ac0f8dea494ac3870ad111261 Mon Sep 17 00:00:00 2001 From: Alexandru Gagniuc Date: Fri, 22 Mar 2019 19:36:51 -0500 Subject: PCI/LINK: Supply IRQ handler so level-triggered IRQs are acked A threaded IRQ with a NULL handler does not work with level-triggered interrupts. request_threaded_irq() will return an error: genirq: Threaded irq requested with handler=NULL and !ONESHOT for irq 16 pcie_bw_notification: probe of 0000:00:1b.0:pcie010 failed with error -22 For level interrupts we need to silence the interrupt before exiting the IRQ handler, so just clear the PCI_EXP_LNKSTA_LBMS bit there. Fixes: e8303bb7a75c ("PCI/LINK: Report degraded links via link bandwidth notification") Reported-by: Linus Torvalds Reported-by: Borislav Petkov Signed-off-by: Alexandru Gagniuc Signed-off-by: Bjorn Helgaas --- drivers/pci/pcie/bw_notification.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/drivers/pci/pcie/bw_notification.c b/drivers/pci/pcie/bw_notification.c index d2eae3b7cc0f..c48746f1cf3c 100644 --- a/drivers/pci/pcie/bw_notification.c +++ b/drivers/pci/pcie/bw_notification.c @@ -44,11 +44,10 @@ static void pcie_disable_link_bandwidth_notification(struct pci_dev *dev) pcie_capability_write_word(dev, PCI_EXP_LNKCTL, lnk_ctl); } -static irqreturn_t pcie_bw_notification_handler(int irq, void *context) +static irqreturn_t pcie_bw_notification_irq(int irq, void *context) { struct pcie_device *srv = context; struct pci_dev *port = srv->port; - struct pci_dev *dev; u16 link_status, events; int ret; @@ -58,6 +57,17 @@ static irqreturn_t pcie_bw_notification_handler(int irq, void *context) if (ret != PCIBIOS_SUCCESSFUL || !events) return IRQ_NONE; + pcie_capability_write_word(port, PCI_EXP_LNKSTA, events); + pcie_update_link_speed(port->subordinate, link_status); + return IRQ_WAKE_THREAD; +} + +static irqreturn_t pcie_bw_notification_handler(int irq, void *context) +{ + struct pcie_device *srv = context; + struct pci_dev *port = srv->port; + struct pci_dev *dev; + /* * Print status from downstream devices, not this root port or * downstream switch port. @@ -67,8 +77,6 @@ static irqreturn_t pcie_bw_notification_handler(int irq, void *context) __pcie_print_link_status(dev, false); up_read(&pci_bus_sem); - pcie_update_link_speed(port->subordinate, link_status); - pcie_capability_write_word(port, PCI_EXP_LNKSTA, events); return IRQ_HANDLED; } @@ -80,7 +88,8 @@ static int pcie_bandwidth_notification_probe(struct pcie_device *srv) if (!pcie_link_bandwidth_notification_supported(srv->port)) return -ENODEV; - ret = request_threaded_irq(srv->irq, NULL, pcie_bw_notification_handler, + ret = request_threaded_irq(srv->irq, pcie_bw_notification_irq, + pcie_bw_notification_handler, IRQF_SHARED, "PCIe BW notif", srv); if (ret) return ret; -- cgit v1.2.3 From 55397ce8df48bdabe56abdc684764529e1334766 Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Wed, 20 Mar 2019 12:05:30 +0100 Subject: PCI/LINK: Clear bandwidth notification interrupt before enabling it When booting a MacBookPro9,1, duplicate link downtraining messages are logged for the devices directly attached to the two CPU-internal Root Ports of the Core i7 3615QM: Once on device enumeration and once on enablement of the bandwidth notification interrupt on the Root Ports. Duplicate messages do not occur with Root Ports on the PCH and Downstream Ports on the Thunderbolt controller: Only a single message is logged for these, namely on device enumeration. The reason for the duplicate messages is a stale interrupt in the Link Status register of the 3615QM's internal Root Ports. Avoid by clearing the interrupt before enabling it. An alternative approach would be to clear the interrupt already on device enumeration or to report link downtraining only if the speed has changed. That way, link downtraining occurring between device enumeration and enablement of the bandwidth notification interrupt could be caught. However clearing stale interrupts before enabling them is a standard operating procedure for any driver and keeping the two steps in one place makes the code easier to follow. Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Alexandru Gagniuc --- drivers/pci/pcie/bw_notification.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/pcie/bw_notification.c b/drivers/pci/pcie/bw_notification.c index c48746f1cf3c..3c0f368c879b 100644 --- a/drivers/pci/pcie/bw_notification.c +++ b/drivers/pci/pcie/bw_notification.c @@ -30,6 +30,8 @@ static void pcie_enable_link_bandwidth_notification(struct pci_dev *dev) { u16 lnk_ctl; + pcie_capability_write_word(dev, PCI_EXP_LNKSTA, PCI_EXP_LNKSTA_LBMS); + pcie_capability_read_word(dev, PCI_EXP_LNKCTL, &lnk_ctl); lnk_ctl |= PCI_EXP_LNKCTL_LBMIE; pcie_capability_write_word(dev, PCI_EXP_LNKCTL, lnk_ctl); -- cgit v1.2.3 From 0fa635aec9abd718bd18c0bda2261351a0811efc Mon Sep 17 00:00:00 2001 From: Lukas Wunner Date: Wed, 20 Mar 2019 12:05:30 +0100 Subject: PCI/LINK: Deduplicate bandwidth reports for multi-function devices If a multi-function device's bandwidth is already limited when it is enumerated, a message is logged only for function 0. By contrast, when downtraining occurs after enumeration, a message is logged for all functions. That's because the former uses pcie_report_downtraining(), whereas the latter uses __pcie_print_link_status() (which doesn't filter functions != 0). I am seeing this happen on a MacBookPro9,1 with a GPU (function 0) and an integrated HDA controller (function 1). Avoid this incongruence by calling pcie_report_downtraining() in both cases. Signed-off-by: Lukas Wunner Signed-off-by: Bjorn Helgaas Reviewed-by: Alexandru Gagniuc --- drivers/pci/pci.h | 1 + drivers/pci/pcie/bw_notification.c | 2 +- drivers/pci/probe.c | 2 +- 3 files changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 224d88634115..d994839a3e24 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -273,6 +273,7 @@ enum pcie_link_width pcie_get_width_cap(struct pci_dev *dev); u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed, enum pcie_link_width *width); void __pcie_print_link_status(struct pci_dev *dev, bool verbose); +void pcie_report_downtraining(struct pci_dev *dev); /* Single Root I/O Virtualization */ struct pci_sriov { diff --git a/drivers/pci/pcie/bw_notification.c b/drivers/pci/pcie/bw_notification.c index 3c0f368c879b..4fa9e3523ee1 100644 --- a/drivers/pci/pcie/bw_notification.c +++ b/drivers/pci/pcie/bw_notification.c @@ -76,7 +76,7 @@ static irqreturn_t pcie_bw_notification_handler(int irq, void *context) */ down_read(&pci_bus_sem); list_for_each_entry(dev, &port->subordinate->devices, bus_list) - __pcie_print_link_status(dev, false); + pcie_report_downtraining(dev); up_read(&pci_bus_sem); return IRQ_HANDLED; diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 2ec0df04e0dc..7e12d0163863 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -2388,7 +2388,7 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn) return dev; } -static void pcie_report_downtraining(struct pci_dev *dev) +void pcie_report_downtraining(struct pci_dev *dev) { if (!pci_is_pcie(dev)) return; -- cgit v1.2.3