This is fix for commit 7897e6022761ace7377f0f784fca059da55f5d71 from v3.9-rc1
("PCI: Disable Bus Master unconditionally in pci_device_shutdown()")
in turn that was fix for b566a22c23327f18ce941ffad0ca907e50a53d41 from v3.5-rc1
("PCI: disable Bus Master on PCI device shutdown")
Unfortunately fixing one bug uncovers another:
->shutdown() callback might switch device to deep sleep state.
PCI config space no longer available after that.
Link: https://lkml.org/lkml/2013/3/12/529
Signed-off-by: Konstantin Khlebnikov <[email protected]>
Reported-and-Tested-by: Vivek Goyal <[email protected]>
Cc: Bjorn Helgaas <[email protected]>
Cc: Rafael J. Wysocki <[email protected]>
---
drivers/pci/pci-driver.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
index 1fa1e48..79277fb 100644
--- a/drivers/pci/pci-driver.c
+++ b/drivers/pci/pci-driver.c
@@ -390,9 +390,10 @@ static void pci_device_shutdown(struct device *dev)
/*
* Turn off Bus Master bit on the device to tell it to not
- * continue to do DMA
+ * continue to do DMA. Don't touch devices in D3cold or unknown states.
*/
- pci_clear_master(pci_dev);
+ if (pci_dev->current_state <= PCI_D3hot)
+ pci_clear_master(pci_dev);
}
#ifdef CONFIG_PM
BUMP. This is degradation from 3.8, so this patch must be in 3.9.
I still don't like this forced clearing bus-master bit. But this hack
definitely fixes problems in kexec, so there is reason to keep it here.
Konstantin Khlebnikov wrote:
> This is fix for commit 7897e6022761ace7377f0f784fca059da55f5d71 from v3.9-rc1
> ("PCI: Disable Bus Master unconditionally in pci_device_shutdown()")
> in turn that was fix for b566a22c23327f18ce941ffad0ca907e50a53d41 from v3.5-rc1
> ("PCI: disable Bus Master on PCI device shutdown")
>
> Unfortunately fixing one bug uncovers another:
> ->shutdown() callback might switch device to deep sleep state.
> PCI config space no longer available after that.
>
> Link: https://lkml.org/lkml/2013/3/12/529
> Signed-off-by: Konstantin Khlebnikov<[email protected]>
> Reported-and-Tested-by: Vivek Goyal<[email protected]>
> Cc: Bjorn Helgaas<[email protected]>
> Cc: Rafael J. Wysocki<[email protected]>
> ---
> drivers/pci/pci-driver.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
> index 1fa1e48..79277fb 100644
> --- a/drivers/pci/pci-driver.c
> +++ b/drivers/pci/pci-driver.c
> @@ -390,9 +390,10 @@ static void pci_device_shutdown(struct device *dev)
>
> /*
> * Turn off Bus Master bit on the device to tell it to not
> - * continue to do DMA
> + * continue to do DMA. Don't touch devices in D3cold or unknown states.
> */
> - pci_clear_master(pci_dev);
> + if (pci_dev->current_state <= PCI_D3hot)
> + pci_clear_master(pci_dev);
> }
>
> #ifdef CONFIG_PM
>
[+cc linux-pci]
On Mon, Apr 1, 2013 at 2:00 AM, Konstantin Khlebnikov
<[email protected]> wrote:
> BUMP. This is degradation from 3.8, so this patch must be in 3.9.
>
> I still don't like this forced clearing bus-master bit. But this hack
> definitely fixes problems in kexec, so there is reason to keep it here.
Applied to for-linus for v3.9, thanks!
> Konstantin Khlebnikov wrote:
>>
>> This is fix for commit 7897e6022761ace7377f0f784fca059da55f5d71 from
>> v3.9-rc1
>> ("PCI: Disable Bus Master unconditionally in pci_device_shutdown()")
>> in turn that was fix for b566a22c23327f18ce941ffad0ca907e50a53d41 from
>> v3.5-rc1
>> ("PCI: disable Bus Master on PCI device shutdown")
>>
>> Unfortunately fixing one bug uncovers another:
>> ->shutdown() callback might switch device to deep sleep state.
>> PCI config space no longer available after that.
>>
>> Link: https://lkml.org/lkml/2013/3/12/529
>> Signed-off-by: Konstantin Khlebnikov<[email protected]>
>> Reported-and-Tested-by: Vivek Goyal<[email protected]>
>> Cc: Bjorn Helgaas<[email protected]>
>> Cc: Rafael J. Wysocki<[email protected]>
>> ---
>> drivers/pci/pci-driver.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
>> index 1fa1e48..79277fb 100644
>> --- a/drivers/pci/pci-driver.c
>> +++ b/drivers/pci/pci-driver.c
>> @@ -390,9 +390,10 @@ static void pci_device_shutdown(struct device *dev)
>>
>> /*
>> * Turn off Bus Master bit on the device to tell it to not
>> - * continue to do DMA
>> + * continue to do DMA. Don't touch devices in D3cold or unknown
>> states.
>> */
>> - pci_clear_master(pci_dev);
>> + if (pci_dev->current_state <= PCI_D3hot)
>> + pci_clear_master(pci_dev);
>> }
>>
>> #ifdef CONFIG_PM
>>
>