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| author | Jesse Barnes <jbarnes@virtuousgeek.org> | 2010-11-05 15:16:36 -0400 |
|---|---|---|
| committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2010-11-11 09:38:14 -0800 |
| commit | 97c145f7c87453cec90e91238fba5fe2c1561b32 (patch) | |
| tree | e69b486547e713b6a9358ad780dcdf7b697a7912 | |
| parent | 3b519e4ea618b6943a82931630872907f9ac2c2b (diff) | |
| download | linux-97c145f7c87453cec90e91238fba5fe2c1561b32.tar.bz2 | |
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>
| -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, int err; int i, bars = 0; + /* + * Power state could be unknown at this point, either due to a fresh + * boot or a device removal call. So get the current power state + * so that things like MSI message writing will behave as expected + * (e.g. if the device really is in D0 at enable time). + */ + if (dev->pm_cap) { + u16 pmcsr; + pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr); + dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK); + } + if (atomic_add_return(1, &dev->enable_cnt) > 1) return 0; /* already enabled */ |