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PCI: read-modify-write the pcie device control register when initiating pcie flr

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The pcie_flr routine writes the device control register with the FLR bit
set clearing all other fields for the FLR duration. Among other fields,
the Max_Payload_Size is also cleared which can cause errors if there are
transactions lurking in the HW pipeline. The patch replaces the blank
write with read-modify-write of the control register keeping the other
fields intact.

Signed-off-by: Shmulik Ravid <shmulikr@broadcom.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Shmulik Ravid 2009-12-03 22:27:51 +02:00 committed by Jesse Barnes
parent bb965401fd
commit 04b55c4732
1 changed files with 5 additions and 3 deletions
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8
drivers/pci/pci.c
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@ -2140,7 +2140,7 @@ static int pcie_flr(struct pci_dev *dev, int probe)
int i;
int pos;
u32 cap;
u16 status;
u16 status, control;
pos = pci_pcie_cap(dev);
if (!pos)
@ -2167,8 +2167,10 @@ static int pcie_flr(struct pci_dev *dev, int probe)
"proceeding with reset anyway\n");
clear:
pci_write_config_word(dev, pos + PCI_EXP_DEVCTL,
PCI_EXP_DEVCTL_BCR_FLR);
pci_read_config_word(dev, pos + PCI_EXP_DEVCTL, &control);
control |= PCI_EXP_DEVCTL_BCR_FLR;
pci_write_config_word(dev, pos + PCI_EXP_DEVCTL, control);
msleep(100);
return 0;