[RFC]disable msi mode in pci_disable_device

[Shaohua Li <shaohua.li@intel.com>]

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>
---

 linux-2.6.17-rc4-root/drivers/pci/msi.c   |    6 ++++--
 linux-2.6.17-rc4-root/drivers/pci/pci.c   |    9 ++++++++-
 linux-2.6.17-rc4-root/include/linux/pci.h |    2 ++
 3 files changed, 14 insertions(+), 3 deletions(-)

diff -puN drivers/pci/msi.c~disable-msi-in-pci_disable_device drivers/pci/msi.c
--- linux-2.6.17-rc4/drivers/pci/msi.c~disable-msi-in-pci_disable_device	2006-05-25 08:18:23.000000000 +0800
+++ linux-2.6.17-rc4-root/drivers/pci/msi.c	2006-05-25 08:25:19.000000000 +0800
@@ -442,9 +442,11 @@ static void enable_msi_mode(struct pci_d
 		/* 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 */
@@ -461,9 +463,11 @@ void disable_msi_mode(struct pci_dev *de
 		/* 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 */
@@ -538,7 +542,6 @@ int pci_save_msi_state(struct pci_dev *d
 		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;
@@ -593,7 +596,6 @@ int pci_save_msix_state(struct pci_dev *
 	}
 	*((u16 *)&save_state->data[0]) = control;
 
-	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;
diff -puN include/linux/pci.h~disable-msi-in-pci_disable_device include/linux/pci.h
--- linux-2.6.17-rc4/include/linux/pci.h~disable-msi-in-pci_disable_device	2006-05-25 08:18:36.000000000 +0800
+++ linux-2.6.17-rc4-root/include/linux/pci.h	2006-05-25 08:19:34.000000000 +0800
@@ -163,6 +163,8 @@ struct pci_dev {
 	unsigned int	is_busmaster:1; /* device is busmaster */
 	unsigned int	no_msi:1;	/* device may not use msi */
 	unsigned int	block_ucfg_access:1;	/* userspace config space access is blocked */
+	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;
diff -puN drivers/pci/pci.c~disable-msi-in-pci_disable_device drivers/pci/pci.c
--- linux-2.6.17-rc4/drivers/pci/pci.c~disable-msi-in-pci_disable_device	2006-05-25 08:20:42.000000000 +0800
+++ linux-2.6.17-rc4-root/drivers/pci/pci.c	2006-05-25 08:32:33.000000000 +0800
@@ -533,7 +533,14 @@ void
 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;
_