PCI/LINK: Remove bandwidth notification

[ Upstream commit b4c7d20 ] The PCIe Bandwidth Change Notification feature logs messages when the link bandwidth changes. Some users have reported that these messages occur often enough to significantly reduce NVMe performance. GPUs also seem to generate these messages. We don't know why the link bandwidth changes, but in the reported cases there's no indication that it's caused by hardware failures. Remove the bandwidth change notifications for now. Hopefully we can add this back when we have a better understanding of why this happens and how we can make the messages useful instead of overwhelming. Link: https://lore.kernel.org/r/20200115221008.GA191037@google.com/ Link: https://lore.kernel.org/r/155605909349.3575.13433421148215616375.stgit@gimli.home/ Link: https://bugzilla.kernel.org/show_bug.cgi?id=206197 Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
xanmod · Mar 17, 2021 · 1490173 · 1490173
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commit 1490173
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diff --git a/drivers/pci/pcie/Kconfig b/drivers/pci/pcie/Kconfig
@@ -133,14 +133,6 @@ config PCIE_PTM
 	  This is only useful if you have devices that support PTM, but it
 	  is safe to enable even if you don't.
 
-config PCIE_BW
-	bool "PCI Express Bandwidth Change Notification"
-	depends on PCIEPORTBUS
-	help
-	  This enables PCI Express Bandwidth Change Notification.  If
-	  you know link width or rate changes occur only to correct
-	  unreliable links, you may answer Y.
-
 config PCIE_EDR
 	bool "PCI Express Error Disconnect Recover support"
 	depends on PCIE_DPC && ACPI

diff --git a/drivers/pci/pcie/Makefile b/drivers/pci/pcie/Makefile
@@ -12,5 +12,4 @@ obj-$(CONFIG_PCIEAER_INJECT)	+= aer_inject.o
 obj-$(CONFIG_PCIE_PME)		+= pme.o
 obj-$(CONFIG_PCIE_DPC)		+= dpc.o
 obj-$(CONFIG_PCIE_PTM)		+= ptm.o
-obj-$(CONFIG_PCIE_BW)		+= bw_notification.o
 obj-$(CONFIG_PCIE_EDR)		+= edr.o
diff --git a/drivers/pci/pcie/bw_notification.c b/drivers/pci/pcie/bw_notification.c
diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
@@ -53,12 +53,6 @@ int pcie_dpc_init(void);
 static inline int pcie_dpc_init(void) { return 0; }
 #endif
 
-#ifdef CONFIG_PCIE_BW
-int pcie_bandwidth_notification_init(void);
-#else
-static inline int pcie_bandwidth_notification_init(void) { return 0; }
-#endif
-
 /* Port Type */
 #define PCIE_ANY_PORT			(~0)
 

diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
@@ -255,7 +255,6 @@ static void __init pcie_init_services(void)
 	pcie_pme_init();
 	pcie_dpc_init();
 	pcie_hp_init();
-	pcie_bandwidth_notification_init();
 }
 
 static int __init pcie_portdrv_init(void)