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authorBjorn Helgaas <bhelgaas@google.com>2017-09-15 01:33:51 -0500
committerBjorn Helgaas <bhelgaas@google.com>2017-09-15 01:33:51 -0500
commit0f50a49e3008597abed0fff052d487f77db89093 (patch)
treeb17952af59d6112187c5b5663fc546f9401adc3d
parent711aab1dbb324d321e3d84368a435a78908c7bce (diff)
downloadlinux-0f50a49e3008597abed0fff052d487f77db89093.tar.bz2
Revert "PCI: Avoid race while enabling upstream bridges"
This reverts commit 40f11adc7cd9281227f0a6a627d966dd0a5f0cd9. Jens found that iwlwifi firmware loading failed on a Lenovo X1 Carbon, gen4: iwlwifi 0000:04:00.0: Direct firmware load for iwlwifi-8000C-34.ucode failed with error -2 iwlwifi 0000:04:00.0: Direct firmware load for iwlwifi-8000C-33.ucode failed with error -2 iwlwifi 0000:04:00.0: Direct firmware load for iwlwifi-8000C-32.ucode failed with error -2 iwlwifi 0000:04:00.0: loaded firmware version 31.532993.0 op_mode iwlmvm iwlwifi 0000:04:00.0: Detected Intel(R) Dual Band Wireless AC 8260, REV=0x208 ... iwlwifi 0000:04:00.0: Failed to load firmware chunk! iwlwifi 0000:04:00.0: Could not load the [0] uCode section iwlwifi 0000:04:00.0: Failed to start INIT ucode: -110 iwlwifi 0000:04:00.0: Failed to run INIT ucode: -110 He bisected it to 40f11adc7cd9 ("PCI: Avoid race while enabling upstream bridges"). Revert that commit to fix the regression. Link: http://lkml.kernel.org/r/4bcbcbc1-7c79-09f0-5071-bc2f53bf6574@kernel.dk Fixes: 40f11adc7cd9 ("PCI: Avoid race while enabling upstream bridges") Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: Srinath Mannam <srinath.mannam@broadcom.com> CC: Jens Axboe <axboe@kernel.dk> CC: Luca Coelho <luca@coelho.fi> CC: Johannes Berg <johannes@sipsolutions.net> CC: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
-rw-r--r--drivers/pci/pci.c13
1 files changed, 2 insertions, 11 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b0002daa50f3..6078dfc11b11 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -52,7 +52,6 @@ static void pci_pme_list_scan(struct work_struct *work);
static LIST_HEAD(pci_pme_list);
static DEFINE_MUTEX(pci_pme_list_mutex);
static DECLARE_DELAYED_WORK(pci_pme_work, pci_pme_list_scan);
-static DEFINE_MUTEX(pci_bridge_mutex);
struct pci_pme_device {
struct list_head list;
@@ -1351,16 +1350,10 @@ static void pci_enable_bridge(struct pci_dev *dev)
if (bridge)
pci_enable_bridge(bridge);
- /*
- * Hold pci_bridge_mutex to prevent a race when enabling two
- * devices below the bridge simultaneously. The race may cause a
- * PCI_COMMAND_MEMORY update to be lost (see changelog).
- */
- mutex_lock(&pci_bridge_mutex);
if (pci_is_enabled(dev)) {
if (!dev->is_busmaster)
pci_set_master(dev);
- goto end;
+ return;
}
retval = pci_enable_device(dev);
@@ -1368,8 +1361,6 @@ static void pci_enable_bridge(struct pci_dev *dev)
dev_err(&dev->dev, "Error enabling bridge (%d), continuing\n",
retval);
pci_set_master(dev);
-end:
- mutex_unlock(&pci_bridge_mutex);
}
static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
@@ -1394,7 +1385,7 @@ static int pci_enable_device_flags(struct pci_dev *dev, unsigned long flags)
return 0; /* already enabled */
bridge = pci_upstream_bridge(dev);
- if (bridge && !pci_is_enabled(bridge))
+ if (bridge)
pci_enable_bridge(bridge);
/* only skip sriov related */