From: Larry Finger Date: Wed, 20 Oct 2010 14:59:33 +0000 (-0500) Subject: ssb: Clear RETRY_TIMEOUT in PCI Configuration for normal devices X-Git-Tag: v2.6.38-rc1~476^2~558^2~134 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e081685c1bbe8da37c7f61726fdb783ff277f14f;p=platform%2Fkernel%2Flinux-3.10.git ssb: Clear RETRY_TIMEOUT in PCI Configuration for normal devices MMIO log traces obtained using the Broadcom wl hybrid driver show that the RETRY_TIMEOUT register (0x41) in PCI configuration space is cleared if non-zero. Similar code found in other drivers such as ipw2100 show this operation is needed to keep PCI Tx retries from interfering with C3 CPU state. There are no known cases where omission of this code has caused a problem, but this patch is offered just in case such a situation occurs. Signed-off-by: Larry Finger Signed-off-by: John W. Linville --- diff --git a/drivers/ssb/pcihost_wrapper.c b/drivers/ssb/pcihost_wrapper.c index 6536a04..f6c8c81 100644 --- a/drivers/ssb/pcihost_wrapper.c +++ b/drivers/ssb/pcihost_wrapper.c @@ -59,6 +59,7 @@ static int ssb_pcihost_probe(struct pci_dev *dev, struct ssb_bus *ssb; int err = -ENOMEM; const char *name; + u32 val; ssb = kzalloc(sizeof(*ssb), GFP_KERNEL); if (!ssb) @@ -74,6 +75,12 @@ static int ssb_pcihost_probe(struct pci_dev *dev, goto err_pci_disable; pci_set_master(dev); + /* Disable the RETRY_TIMEOUT register (0x41) to keep + * PCI Tx retries from interfering with C3 CPU state */ + pci_read_config_dword(dev, 0x40, &val); + if ((val & 0x0000ff00) != 0) + pci_write_config_dword(dev, 0x40, val & 0xffff00ff); + err = ssb_bus_pcibus_register(ssb, dev); if (err) goto err_pci_release_regions;