pcim_intx() tries to restore the INTX_DISABLE bit at removal via
devres, but there is a chance that it restores a wrong value.
Because the value to be restored is blindly assumed to be the negative
of the enable argument, when a driver calls pcim_intx() unnecessarily
for the already enabled state, it'll restore to the disabled state in
turn. Also, when a driver calls pcim_intx() multiple times with
different enable argument values, the last one will win no matter what
value it is.
This patch addresses those inconsistencies by saving the original
INTX_DISABLE state at the first devres_alloc(); this assures that the
original state is restored properly, and the later pcim_intx() calls
won't overwrite res->orig_intx any longer.
Fixes: 25216afc9db5 ("PCI: Add managed pcim_intx()")
Link: https://lore.kernel.org/87v7xk2ps5.wl-tiwai@xxxxxxx
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
---
drivers/pci/devres.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
index b133967faef8..aed3c9a355cb 100644
--- a/drivers/pci/devres.c
+++ b/drivers/pci/devres.c
@@ -438,8 +438,17 @@ static void pcim_intx_restore(struct device *dev, void *data)
__pcim_intx(pdev, res->orig_intx);
}
-static struct pcim_intx_devres *get_or_create_intx_devres(struct device *dev)
+static void save_orig_intx(struct pci_dev *pdev, struct pcim_intx_devres *res)
{
+ u16 pci_command;
+
+ pci_read_config_word(pdev, PCI_COMMAND, &pci_command);
+ res->orig_intx = !(pci_command & PCI_COMMAND_INTX_DISABLE);
+}
+
+static struct pcim_intx_devres *get_or_create_intx_devres(struct pci_dev *pdev)
+{
+ struct device *dev = &pdev->dev;
struct pcim_intx_devres *res;
res = devres_find(dev, pcim_intx_restore, NULL, NULL);
@@ -447,8 +456,10 @@ static struct pcim_intx_devres *get_or_create_intx_devres(struct device *dev)
return res;
res = devres_alloc(pcim_intx_restore, sizeof(*res), GFP_KERNEL);
- if (res)
+ if (res) {
+ save_orig_intx(pdev, res);
devres_add(dev, res);
+ }
return res;
}
@@ -467,11 +478,10 @@ int pcim_intx(struct pci_dev *pdev, int enable)
{
struct pcim_intx_devres *res;
- res = get_or_create_intx_devres(&pdev->dev);
+ res = get_or_create_intx_devres(pdev);
if (!res)
return -ENOMEM;
- res->orig_intx = !enable;
__pcim_intx(pdev, enable);
return 0;
--
2.43.0
