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Subject[RFC]disable msi mode in pci_disable_device
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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;
_
-
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