diff options
author | Jesse Barnes <jbarnes@virtuousgeek.org> | 2010-11-05 15:16:36 -0400 |
---|---|---|
committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2010-11-11 12:38:14 -0500 |
commit | 97c145f7c87453cec90e91238fba5fe2c1561b32 (patch) | |
tree | e69b486547e713b6a9358ad780dcdf7b697a7912 /drivers/pci/pci.c | |
parent | 3b519e4ea618b6943a82931630872907f9ac2c2b (diff) |
PCI: read current power state at enable time
When we enable a PCI device, we avoid doing a lot of the initial setup
work if the device's enable count is non-zero. If we don't fetch the
power state though, we may later fail to set up MSI due to the unknown
status. So pick it up before we short circuit the rest due to a
pre-existing enable or mismatched enable/disable pair (as happens with
VGA devices, which are special in a special way).
Tested-by: Jesse Brandeburg <jesse.brandeburg@gmail.com>
Reported-by: Dave Airlie <airlied@linux.ie>
Tested-by: Dave Airlie <airlied@linux.ie>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Diffstat (limited to 'drivers/pci/pci.c')
-rw-r--r-- | drivers/pci/pci.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e98c8104297b..710c8a29be0d 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c | |||
@@ -1007,6 +1007,18 @@ static int __pci_enable_device_flags(struct pci_dev *dev, | |||
1007 | int err; | 1007 | int err; |
1008 | int i, bars = 0; | 1008 | int i, bars = 0; |
1009 | 1009 | ||
1010 | /* | ||
1011 | * Power state could be unknown at this point, either due to a fresh | ||
1012 | * boot or a device removal call. So get the current power state | ||
1013 | * so that things like MSI message writing will behave as expected | ||
1014 | * (e.g. if the device really is in D0 at enable time). | ||
1015 | */ | ||
1016 | if (dev->pm_cap) { | ||
1017 | u16 pmcsr; | ||
1018 | pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); | ||
1019 | dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); | ||
1020 | } | ||
1021 | |||
1010 | if (atomic_add_return(1, &dev->enable_cnt) > 1) | 1022 | if (atomic_add_return(1, &dev->enable_cnt) > 1) |
1011 | return 0; /* already enabled */ | 1023 | return 0; /* already enabled */ |
1012 | 1024 | ||