On Fri, Jul 11, 2014 at 10:38 AM, Alexandre Courbot <acour...@nvidia.com> wrote: > Hi Ben, > > > On 07/11/2014 10:07 AM, Ben Skeggs wrote: >> >> On Thu, Jul 10, 2014 at 5:34 PM, Alexandre Courbot <acour...@nvidia.com> >> wrote: >>> >>> This series adds support for reclocking on GK20A. The first two patches >>> touch >>> the clock subsystem to allow GK20A to operate, by making the presence of >>> the >>> thermal and voltage devices optional, and allowing pstates to be provided >>> directly instead of being probed using the BIOS (which Tegra does not >>> have). >> >> Hey Alex, >> >> I mentioned a while back I had some stuff in-progress to make >> implementing this a bit cleaner for you, but as you can probably tell, >> I didn't get to it yet. It's likely I won't manage to before the next >> merge window either. So, I'll likely take these patches as-is >> (assuming no objections on reviews here) and rebase my stuff on top. > > > Thanks. You will probably notice that these patches won't apply to your tree > and require some tweaking. I will probably end up sending a v2 anyway, so > maybe you should wait for it. If you want to try this version anyway, I have > fixed-up patches against your tree. > > Note that your tree currently won't build against -next because it uses > drm_sysfs_connector_add/remove which are not available anymore (replaced by > drm_connector_register/unregister I believe). > > Oh and while I'm at it, there seems to be a typo in line 131 of clock.h, > which should read _nouveau_clock_fini and not _nouveau_clock_init. > > >>> >>> The last patch adds the GK20A clock device. Arguably the clock can be >>> seen as a >>> stripped-down version of what is seen on NVE0, however instead of using >>> NVE0 >>> support has been written from scratch using the ChromeOS kernel as a >>> basis. >>> There are several reasons for this: >>> >>> - The ChromeOS driver uses a lookup table for the P coefficient which I >>> could >>> not find in the NVE0 driver, >> >> Interesting. Can you give more details on how "PL" works exactly, >> we'd been operating on the assumption (mainly inherited from code that >> appeared in xf86-video-nv) that it was always a straight division. > > > The pl_to_div table in clock/gk20a.c should give the right coefficients, but > I have seen contradictory information in our docs. Let me ask the right > people so we can get to the bottom of this.
So as it turns out this seems to be gk20a-specific. Other Kepler GPUs use it as a straight division, but gk20a uses a narrower range and thus requires this table. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
