Inspired by Russell King's patch[1], I found current tegra also has the same issue of "reading 32-bits from the command register, modifying the command register, and then writing it back has the effect of clearing any status bits that were indicating at that time" as pointed out by Russell. This patch fix this issue by using the pci_generic_config_write. [1]http://www.spinics.net/lists/linux-pci/msg44869.html Signed-off-by: Jisheng Zhang <jszhang@xxxxxxxxxxx> --- drivers/pci/host/pci-tegra.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/pci/host/pci-tegra.c b/drivers/pci/host/pci-tegra.c index 81df0c1..d926e3e 100644 --- a/drivers/pci/host/pci-tegra.c +++ b/drivers/pci/host/pci-tegra.c @@ -483,7 +483,7 @@ static void __iomem *tegra_pcie_conf_address(struct pci_bus *bus, static struct pci_ops tegra_pcie_ops = { .map_bus = tegra_pcie_conf_address, .read = pci_generic_config_read32, - .write = pci_generic_config_write32, + .write = pci_generic_config_write, }; static unsigned long tegra_pcie_port_get_pex_ctrl(struct tegra_pcie_port *port) -- 2.6.2 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html