Re: enable i915 rc6 save 7 watt on kernel 3.2
Am Donnerstag, 19. Januar 2012 schrieb Chen Wei:
> On Thu, Jan 19, 2012 at 01:05:13PM +0100, Martin Steigerwald wrote:
> > > wei@Tungsten:~$ dmesg|grep -i aspm
> > > [ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-3.2.1
> > > root=UUID=ed888aee-0822-4303-8bea-18f0fbf9ba3a ro quiet
> > > pcie_aspm=force threadirqs
> > > [ 0.000000] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-3.2.1
> > > root=UUID=ed888aee-0822-4303-8bea-18f0fbf9ba3a ro quiet
> > > pcie_aspm=force threadirqs
> > > [ 0.000000] PCIe ASPM is forcibly enabled
> > > [ 0.460586] ACPI FADT declares the system doesn't support PCIe
> > > ASPM, so disable it
> > > [ 0.582432] ACPI _OSC control for PCIe not granted, disabling
> > > ASPM
> >
> > Well AFAIR the second message is overridden by the first one in that
> > case. Would have to lookup the details from some Phoronix articles
> > by Michael Larabel or some other sources or the linux kernel source.
>
> good to know. any chance it may cause hardware damage on unsupported
> BIOS?
As far as I understood it would just not work without damaging the
hardware. But no warranties from my side ;).
> > > > while games and compositing managers use a different and larger
> > > > set of OpenGL. There are some benchmarks at Phoronix that show
> > > > increased framerates. One suggested explaination there is that
> > > > due to the
> > >
> > > they are over several hundred MB. Is there any small and simple
> > > graphic test tool like glxgreas?
> >
> > Well what exactly do you want to test and why?
>
> not long ago on this list, when I mentioned glxgears score, I was
> suggested to benchmarking by flightgears, which is also several hundred
> MB. I am simply curious why graphic test suits are all so big.
Well flightgear is a game, not a graphics test suite. And this party
describes the challenge.
OpenGL applications use a varying amount of OpenGL commands and features
and so to measure their speed you would need to have a testsuite that uses
the same set of commands and features in a similar way. Now, there might
be benchmarks that try to do this, but glxgears AFAIK doesn´t even try to
do it. glxgears is just a plain and simple OpenGL example.
> Although T520 is overkill for google earth(constant blinking, but it is
> another story), the most graphic demanding apps I use, I have a strong
> feeling that higher graphic score on the same hardware could means more
> efficient way of using GPU, therefore possible lower power usage when
> running non graphical intense apps, hence longer battery life. My
> feeling, well, is just feeling, since the power meter shows regardless
> the glxgears score, the typical desktop usage use almost same amount of
> power under different kernel. Anyway, it is always good to know that
> more juice can be squeezed out of the same hardware, isn't it?
Well for me its enough to see that the OpenGL performance of Intel
Sandybridge meanwhile with the newer drivers is more than enough to handle
an OpenGL composited KDE SC desktop - especially since 4.7, since kwin
received notable optimizations - with full HD resolution (1920x1080).
It is also enough to handle Supertuxkart, Freedroid RPG at full HD
resolution and some other games at their highest resolutions.
A very simple performance indicator of KWin´s compositing is the FPS
display effect. Or the FPS displays in various games. But then even there
could be some limitation in place. Freedroid RPG for example limits
framerate for lower power consumption to something over what the human eye
can still notice. And kwin has a vsync option.
For me its also enough to see that since RC6 by battery goes longer than I
need ;). Even the 6-cell one is impressive, but the 9-cell one lasts a
work day. Of course, when you are into tuning your laptop for the latest
watt or are developer you might want to dig deeper than hat.
First I didn´t believe that one can equip a Sandybridge ThinkPad with so
much batteries that it would run 24 hours as I think that Lenovo
advertised. Now I do. As far as I know its possible to use a 9-cell
battery, a ultrabay battery and a battery under the laptop simultaneously,
but I am not completely sure.
Ciao,
--
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA B82F 991B EAAC A599 84C7
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