http://bugs.freedesktop.org/show_bug.cgi?id=26347
--- Comment #11 from Tobias Jakobi <liquid.a...@gmx.net> 2010-02-04 15:51:29 PST --- I checked the Windows driver behaviour with my friend (who owns a integrated Radeon HD in his laptop) and it seems to go like this: The driver selects a powerstate based on the energy-level of the system (by watching for ACPI events). With the information from DRM radeon we found out that the VGA BIOS does feature 4 power states. But only state 1 and 2 are used by the Windows driver, state 0 and 3 are never used. If the laptop is running on battery mode the driver switches to power state 1, if the laptop is running on AC it's switched to power state 2. I don't have all details memorized, but the maximum GPU clock for this chip is 500MHz and the AC power state has both 500MHz and 330MHz CPU clocks. The battery power state has 330MHz and 110MHz GPU clocks. Again, the powerstate never changes if one does not fiddle with the AC cord. Doing some testing with FurMark the driver only reclocks with the clocks from the current power state. If it's on battery and there is no load on the GPU it's downclocked to 100MHz - going up to 330MHz once FurMark kicks in. Same goes for the AC power state. We need the same for DRM radeon: Something (devicenode in /sys/ e.g.) that can select the power state, so I can configure acpid to select the appropriate powerstate on AC/battery changes OR do it manually. Then the driver should only reclock with the clocks that are inside the clock group belonging to the power state. Creating custom power states would be an additional goodie, so you can tweak the hardware even more (something like VERY low power states - example: reducing mem clock on my card since all the existant powerstates always clock it at MAX). -- Configure bugmail: http://bugs.freedesktop.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are the assignee for the bug. ------------------------------------------------------------------------------ The Planet: dedicated and managed hosting, cloud storage, colocation Stay online with enterprise data centers and the best network in the business Choose flexible plans and management services without long-term contracts Personal 24x7 support from experience hosting pros just a phone call away. http://p.sf.net/sfu/theplanet-com -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
