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authorKhalid Aziz <khalid.aziz@oracle.com>2013-11-27 15:19:25 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-12-20 07:45:08 -0800
commit2a038881b601a81b522fa4bd3dfc8ccfafd34202 (patch)
treed4517053a195474d1687c32beee732727319eb3e /drivers/pci
parentf75eb9d4085192dc58c30a9384cf4496194be851 (diff)
PCI: Disable Bus Master only on kexec reboot
commit 4fc9bbf98fd66f879e628d8537ba7c240be2b58e upstream. Add a flag to tell the PCI subsystem that kernel is shutting down in preparation to kexec a kernel. Add code in PCI subsystem to use this flag to clear Bus Master bit on PCI devices only in case of kexec reboot. This fixes a power-off problem on Acer Aspire V5-573G and likely other machines and avoids any other issues caused by clearing Bus Master bit on PCI devices in normal shutdown path. The problem was introduced by b566a22c2332 ("PCI: disable Bus Master on PCI device shutdown"). This patch is based on discussion at http://marc.info/?l=linux-pci&m=138425645204355&w=2 Link: https://bugzilla.kernel.org/show_bug.cgi?id=63861 Reported-by: Chang Liu <cl91tp@gmail.com> Signed-off-by: Khalid Aziz <khalid.aziz@oracle.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Konstantin Khlebnikov <koct9i@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/pci')
-rw-r--r--drivers/pci/pci-driver.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 79277fb36c6..66aabde8272 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -19,6 +19,7 @@
#include <linux/cpu.h>
#include <linux/pm_runtime.h>
#include <linux/suspend.h>
+#include <linux/kexec.h>
#include "pci.h"
struct pci_dynid {
@@ -388,12 +389,17 @@ static void pci_device_shutdown(struct device *dev)
pci_msi_shutdown(pci_dev);
pci_msix_shutdown(pci_dev);
+#ifdef CONFIG_KEXEC
/*
- * Turn off Bus Master bit on the device to tell it to not
- * continue to do DMA. Don't touch devices in D3cold or unknown states.
+ * If this is a kexec reboot, turn off Bus Master bit on the
+ * device to tell it to not continue to do DMA. Don't touch
+ * devices in D3cold or unknown states.
+ * If it is not a kexec reboot, firmware will hit the PCI
+ * devices with big hammer and stop their DMA any way.
*/
- if (pci_dev->current_state <= PCI_D3hot)
+ if (kexec_in_progress && (pci_dev->current_state <= PCI_D3hot))
pci_clear_master(pci_dev);
+#endif
}
#ifdef CONFIG_PM