<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [snb] backlight issue on TOSHIBA PORTEGE R830 after suspend/resume" href="https://bugs.freedesktop.org/show_bug.cgi?id=82634#c21">Comment # 21</a> on <a class="bz_bug_link bz_status_REOPENED " title="REOPENED - [snb] backlight issue on TOSHIBA PORTEGE R830 after suspend/resume" href="https://bugs.freedesktop.org/show_bug.cgi?id=82634">bug 82634</a> from <a class="email" href="mailto:jani.nikula@intel.com" title="Jani Nikula <jani.nikula@intel.com>"> Jani Nikula</a> <pre>(In reply to Hans de Goede from <a href="show_bug.cgi?id=82634#c19">comment #19</a>) > Also having 2 pieces of code (the i915 driver and the firmware) poling at > the same registers during suspend / resume is just wrong, that it happens to > often work does not make it less wrong, we really should always be loading > either the i915 or the acpi-video backlight driver and not both. Depending on the machine, the firmware might actually ask i915 to adjust the brightness through the ACPI opregion. So only one entity actually touches the backlight registers, with locks held, but there are two interfaces for it. This appears to be the case here too, and your patch disables the ACPI interface as well. One could try disabling just the registering of the intel_backlight sysfs interface. (Of course, there are also machines where the firmware messes with the backlight registers directly also. I don't know how to distinguish those.)</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> <li>You are on the CC list for the bug.</li> <li>You are the assignee for the bug.</li> </ul> </body> </html>