[PATCH] PCI: disable msi mode in pci_disable_device

Brice said the pci_save_msi_state breaks his driver in his special usage
(not in suspend/resume), as pci_save_msi_state will disable msi mode. In
his usage, pci_save_state will be called at runtime, and later (after
the device operates for some time and has an error) pci_restore_state
will be called.
In another hand, suspend/resume needs disable msi mode, as device should
stop working completely. This patch try to workaround this issue.
Drivers are expected call pci_disable_device in suspend time after
pci_save_state.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/msi.c

@@ -453,9 +453,11 @@ static void enable_msi_mode(struct pci_dev *dev, int pos, int type)
 		/* Set enabled bits to single MSI & enable MSI_enable bit */
 		msi_enable(control, 1);
 		pci_write_config_word(dev, msi_control_reg(pos), control);
+		dev->msi_enabled = 1;
 	} else {
 		msix_enable(control);
 		pci_write_config_word(dev, msi_control_reg(pos), control);
+		dev->msix_enabled = 1;
 	}
     	if (pci_find_capability(dev, PCI_CAP_ID_EXP)) {
 		/* PCI Express Endpoint device detected */
@@ -472,9 +474,11 @@ void disable_msi_mode(struct pci_dev *dev, int pos, int type)
 		/* Set enabled bits to single MSI & enable MSI_enable bit */
 		msi_disable(control);
 		pci_write_config_word(dev, msi_control_reg(pos), control);
+		dev->msi_enabled = 0;
 	} else {
 		msix_disable(control);
 		pci_write_config_word(dev, msi_control_reg(pos), control);
+		dev->msix_enabled = 0;
 	}
     	if (pci_find_capability(dev, PCI_CAP_ID_EXP)) {
 		/* PCI Express Endpoint device detected */
@@ -549,7 +553,6 @@ int pci_save_msi_state(struct pci_dev *dev)
 		pci_read_config_dword(dev, pos + PCI_MSI_DATA_32, &cap[i++]);
 	if (control & PCI_MSI_FLAGS_MASKBIT)
 		pci_read_config_dword(dev, pos + PCI_MSI_MASK_BIT, &cap[i++]);
-	disable_msi_mode(dev, pos, PCI_CAP_ID_MSI);
 	save_state->cap_nr = PCI_CAP_ID_MSI;
 	pci_add_saved_cap(dev, save_state);
 	return 0;
@@ -639,7 +642,6 @@ int pci_save_msix_state(struct pci_dev *dev)
 	}
 	dev->irq = temp;
 
-	disable_msi_mode(dev, pos, PCI_CAP_ID_MSIX);
 	save_state->cap_nr = PCI_CAP_ID_MSIX;
 	pci_add_saved_cap(dev, save_state);
 	return 0;

drivers/pci/pci.c

@@ -552,6 +552,13 @@ pci_disable_device(struct pci_dev *dev)
 {
 	u16 pci_command;
 
+	if (dev->msi_enabled)
+		disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
+			PCI_CAP_ID_MSI);
+	if (dev->msix_enabled)
+		disable_msi_mode(dev, pci_find_capability(dev, PCI_CAP_ID_MSI),
+			PCI_CAP_ID_MSIX);
+
 	pci_read_config_word(dev, PCI_COMMAND, &pci_command);
 	if (pci_command & PCI_COMMAND_MASTER) {
 		pci_command &= ~PCI_COMMAND_MASTER;

include/linux/pci.h

@@ -163,6 +163,8 @@ struct pci_dev {
 	unsigned int	no_msi:1;	/* device may not use msi */
 	unsigned int	block_ucfg_access:1;	/* userspace config space access is blocked */
 	unsigned int	broken_parity_status:1;	/* Device generates false positive parity */
+	unsigned int 	msi_enabled:1;
+	unsigned int	msix_enabled:1;
 
 	u32		saved_config_space[16]; /* config space saved at suspend time */
 	struct hlist_head saved_cap_space;