July 2013


Intel16 Jul 2013 02:15 pm

This is the first post in the Power Savings post series I’m just starting to write.

I know there is nothing really new and exciting in this post once RC6 is a feature available for a coupe of years now and already enabled by default at our driver. However is the easiest topic to start with and I couldn’t let it out of the list, mainly because this is the most efficient power saving feature supported by our driver so far.

RC6 stands for Render C-State which is a low voltage state for the graphics processor. This state is entered when the graphics render engine, blitter engine and the video engine have no workload being currently worked and no outstanding graphics memory transactions.

Currently our kernel driver (i915) supports RC6 only for  2nd Generation Intel® Core™ Processors with Intel® HD Graphics (SandyBridge), 3rd Generation Intel® Core™ Processors with Intel® HD Graphics (IvyBridge) and 4th Generation Intel® Core™ Processors with Intel® HD Graphics (Haswell).

One frequent question is: how many render states does Intel GPU has, i.e. does it has RC1, RC2, RC3, RC4, RC5? The answer is: No, we only have RC6. Or GPU is on RC6 state or it is out. Low voltage or Normal voltage. However on SandyBridge and IvyBridge there are deep RC6 (RC6p) and deepest RC6  (RC6pp) states available, what means even lower voltage states. By default on SandyBridge only RC6 is enabled and on IvyBridge both RC6 and deep RC6 are enabled.

In Haswell RC6 is also enabled by default.

In order to change default configurations you must give kernel cmdline boot flag: i915.enable_rc6, where different stages can be selected via bitmask values. (0 = disable; 1 = enable rc6; 2 = enable deep rc6; 4 = enable deepest rc6). For example, 3 would enable rc6 and deep rc6, and 7 would enable everything.

Most of known issues caused by RC6 are GPU hangs. So if you are facing any gpu hung or any other issue we recommend you to disabled by using  i915.enable_rc6=0 and report a bug at  https://bugs.freedesktop.org following  our How to report bugs tutorial.

 

Intel16 Jul 2013 02:15 pm

Today I’m going to start a series of posts giving  an overview about the power savings features present, or under development, in i915 (Intel Graphics Linux Kernel Driver).

Features covered for now in this series will be:

Besides the overview I’m going to detail current implementation status at our driver, how to enable/disable, how to check running status and list known issues.

It is important to say beforehand that some of these power savings features can impact rendering performance, mainly 3D, and sometimes cause some known GPU hangs. So, if you aren’t a hardcore user and is desperate to make your laptop’s battery last a bit longer you might give a chance and try them out.

Also if you find any new bug we encourage you report the bug at https://bugs.freedesktop.org following  our How to report bugs tutorial.

Intel11 Jul 2013 03:57 pm

I’m glad to share that 2013Q2 Intel Linux Graphics Stack was released this week at https://01.org/linuxgraphics/downloads/2013/2013q2-intel-graphics-stack-release.

The 2013Q2 highlights are: bug fixes, performance improvements, new hardware-accelerated media encoding formats, and additional hardware-accelerated video processing features.

On the last releases we are trying to improve the release notes adding more and more useful information highlighting new features and critical fixed bugs. But if you follow all release notes you probably noticed that at this time there is a mix between technical info with Marketing names and information in an easy language for non technical users. This is a reflex of new kind of users accessing 01.org/linuxgraphics website we got after we provided 1 click installer tool that allows even non technical end users to upgrade their Intel graphics stack to the latest one available.

If you have any comments or suggestions about how to improve stack release, release notes or installer don’t be shy and use our Forum.

We are now working to release next Installer version soon that will allow  users to upgrade their Fedora 19 or Ubuntu 13.04 to our 2013Q2 stack.