From 9a9f6a9487201e4c80338e771eec28067f044240 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Thu, 13 Feb 2014 16:18:43 +0000 Subject: uxa: Check for access to backlight interface Before attaching properties to any connector, check that we can indeed control the backlight through the sysfs interface by doing an access check. If the xserver is started without root privileges, we cannot write through /sys/class/backlight and so should take care not to advertise that we can. Reported-by: Hans de Geode Signed-off-by: Chris Wilson --- src/uxa/intel_display.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/src/uxa/intel_display.c b/src/uxa/intel_display.c index a4e04ec4..e1b29201 100644 --- a/src/uxa/intel_display.c +++ b/src/uxa/intel_display.c @@ -298,6 +298,14 @@ intel_output_backlight_get_max(xf86OutputPtr output) char path[BACKLIGHT_PATH_LEN], val[BACKLIGHT_VALUE_LEN]; int fd, max = 0; + /* We are used as an initial check to see if we can + * control the backlight, so first test if we can set values. + */ + sprintf(path, "%s/%s/brightness", + BACKLIGHT_CLASS, intel_output->backlight_iface); + if (access(path, R_OK | W_OK)) + return -1; + sprintf(path, "%s/%s/max_brightness", BACKLIGHT_CLASS, intel_output->backlight_iface); fd = open(path, O_RDONLY); -- cgit v1.2.3