From: Emil Velikov <emil.veli...@collabora.com> Currently the revision isn't available via sysfs/libudev thus if one wants to know the value they need to read through the config file.
This in itself wakes/powers up the device, causing unwanted delays. There are at least two userspace components which could make use the new file - libpciaccess and libdrm. At the moment the former will wake up _every_ PCI device for simple invocation of glxinfo [when using Mesa 10.0+ drivers]. While the latter [in association with Mesa 13.0] can lead to 2-3 second delays while starting firefox, thunderbird or chromium. Expose the revision as a separate file, just like we do for the device, vendor, their subsystem version and class. Cc: Bjorn Helgaas <bhelgaas at google.com> Cc: linux-pci at vger.kernel.org Link: https://bugs.freedesktop.org/show_bug.cgi?id=98502 Tested-by: Mauro Santos <registo.mailling at gmail.com> Reviewed-by: Alex Deucher <alexander.deucher at amd.com> Signed-off-by: Emil Velikov <emil.velikov at collabora.com> --- v2: - Add r-b/t-b tags - Slim down CC list - Add note about userspace. As before, please keep me in the CC list. Additionally if there's anything else I can do to get things going please let me know. Thanks Emil --- drivers/pci/pci-sysfs.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index bcd10c7..0666287 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -50,6 +50,7 @@ pci_config_attr(vendor, "0x%04x\n"); pci_config_attr(device, "0x%04x\n"); pci_config_attr(subsystem_vendor, "0x%04x\n"); pci_config_attr(subsystem_device, "0x%04x\n"); +pci_config_attr(revision, "0x%02x\n"); pci_config_attr(class, "0x%06x\n"); pci_config_attr(irq, "%u\n"); @@ -568,6 +569,7 @@ static struct attribute *pci_dev_attrs[] = { &dev_attr_device.attr, &dev_attr_subsystem_vendor.attr, &dev_attr_subsystem_device.attr, + &dev_attr_revision.attr, &dev_attr_class.attr, &dev_attr_irq.attr, &dev_attr_local_cpus.attr, -- 2.9.3
