[PATCH 1/2] PCI: Make pci_msi_setup_pci_dev() non-static for use by arch code

From: "Guilherme G. Piccoli" <redacted>

Commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel
doesn't support MSI") changed the location of the code that initialises
dev->msi_cap/msix_cap and then disables MSI/MSI-X interrupts at PCI
probe time in devices that have this flag set. It moved the code from
pci_msi_init_pci_dev() to a new function named pci_msi_setup_pci_dev(),
called by pci_setup_device().

The pseries PCI probing code does not call pci_setup_device(), so since
the aforementioned commit the function pci_msi_setup_pci_dev() is not
called and MSI/MSI-X interrupts are left enabled. Additionally because
dev->msi_cap/msix_cap are not initialised no driver can ever enable
MSI/MSI-X.

To fix this, the pseries PCI probe should manually call
pci_msi_setup_pci_dev(), so this patch makes it non-static.

Fixes: 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI")
[mpe: Update change log to mention dev->msi_cap/msix_cap]
Signed-off-by: Guilherme G. Piccoli <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 drivers/pci/probe.c | 2 +-
 include/linux/pci.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)


Bjorn, I plan to put this series in my fixes branch and ask Linus to pull it
before the 4.2 release. Unless you want to take it.

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index b978bbfe044c..f6ae0d0052eb 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c

@@ -1108,7 +1108,7 @@ int pci_cfg_space_size(struct pci_dev *dev)
 
 #define LEGACY_IO_RESOURCE	(IORESOURCE_IO | IORESOURCE_PCI_FIXED)
 
-static void pci_msi_setup_pci_dev(struct pci_dev *dev)
+void pci_msi_setup_pci_dev(struct pci_dev *dev)
 {
 	/*
 	 * Disable the MSI hardware to avoid screaming interrupts

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8a0321a8fb59..860c751810fc 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h

@@ -1202,6 +1202,7 @@ struct msix_entry {
 	u16	entry;	/* driver uses to specify entry, OS writes */
 };
 
+void pci_msi_setup_pci_dev(struct pci_dev *dev);
 
 #ifdef CONFIG_PCI_MSI
 int pci_msi_vec_count(struct pci_dev *dev);

-- 
2.1.4

From: "Guilherme G. Piccoli" <redacted>

Since commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if
kernel doesn't support MSI"), the setup of dev->msi_cap/msix_cap and the
disable of MSI/MSI-X interrupts isn't being done at PCI probe time, as
the logic responsible for this was moved in the aforementioned commit
from pci_device_add() to pci_setup_device(). The latter function is not
reachable on PowerPC pseries platform during Open Firmware PCI probing
time.

This exhibits as drivers not being able to enable MSI, eg:

  bnx2x 0000:01:00.0: no msix capability found

This patch calls pci_msi_setup_pci_dev() explicitly to disable MSI/MSI-X
during PCI probe time on pSeries platform.

Fixes: 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI")
[mpe: Flesh out change log and clarify comment]
Signed-off-by: Guilherme G. Piccoli <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
 arch/powerpc/kernel/pci_of_scan.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/kernel/pci_of_scan.c b/arch/powerpc/kernel/pci_of_scan.c
index 42e02a2d570b..efc3fa54c90b 100644
--- a/arch/powerpc/kernel/pci_of_scan.c
+++ b/arch/powerpc/kernel/pci_of_scan.c

@@ -191,6 +191,9 @@ struct pci_dev *of_create_pci_dev(struct device_node *node,
 
 	pci_device_add(dev, bus);
 
+	/* Setup MSI caps & disable MSI/MSI-X interrupts */
+	pci_msi_setup_pci_dev(dev);
+
 	return dev;
 }
 EXPORT_SYMBOL(of_create_pci_dev);

-- 
2.1.4

On Mon, 2015-24-08 at 12:42:46 UTC, Michael Ellerman wrote:

From: "Guilherme G. Piccoli" <redacted>

Commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel
doesn't support MSI") changed the location of the code that initialises
dev->msi_cap/msix_cap and then disables MSI/MSI-X interrupts at PCI
probe time in devices that have this flag set. It moved the code from
pci_msi_init_pci_dev() to a new function named pci_msi_setup_pci_dev(),
called by pci_setup_device().

The pseries PCI probing code does not call pci_setup_device(), so since
the aforementioned commit the function pci_msi_setup_pci_dev() is not
called and MSI/MSI-X interrupts are left enabled. Additionally because
dev->msi_cap/msix_cap are not initialised no driver can ever enable
MSI/MSI-X.

To fix this, the pseries PCI probe should manually call
pci_msi_setup_pci_dev(), so this patch makes it non-static.

Fixes: 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI")
[mpe: Update change log to mention dev->msi_cap/msix_cap]
Signed-off-by: Guilherme G. Piccoli <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Applied to powerpc fixes.

https://git.kernel.org/powerpc/c/22b6839b914bbe5d94de11bb

cheers

On Mon, 2015-24-08 at 12:42:47 UTC, Michael Ellerman wrote:

From: "Guilherme G. Piccoli" <redacted>

Since commit 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if
kernel doesn't support MSI"), the setup of dev->msi_cap/msix_cap and the
disable of MSI/MSI-X interrupts isn't being done at PCI probe time, as
the logic responsible for this was moved in the aforementioned commit
from pci_device_add() to pci_setup_device(). The latter function is not
reachable on PowerPC pseries platform during Open Firmware PCI probing
time.

This exhibits as drivers not being able to enable MSI, eg:

  bnx2x 0000:01:00.0: no msix capability found

This patch calls pci_msi_setup_pci_dev() explicitly to disable MSI/MSI-X
during PCI probe time on pSeries platform.

Fixes: 1851617cd2da ("PCI/MSI: Disable MSI at enumeration even if kernel doesn't support MSI")
[mpe: Flesh out change log and clarify comment]
Signed-off-by: Guilherme G. Piccoli <redacted>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

Applied to powerpc fixes.

https://git.kernel.org/powerpc/c/4d9aac397a5d8f4ee26a4178

cheers