On Tue, Jan 19, 2016 at 5:22 AM, Jiri Slaby <jslaby@xxxxxxx> wrote: > Hi, > > On 01/17/2016, 08:28 PM, Ilia Mirkin wrote: >> I'd like to recommend backporting this commit: >> >> commit 0a363e85cdafbceeee6a49b91c604d0d4d070dc7 >> Author: Hans de Goede <hdegoede@xxxxxxxxxx> >> Date: Thu Jul 23 17:20:12 2015 +0200 >> >> drm/nouveau/nv46: Change mc subdev oclass from nv44 to nv4c >> >> This disables MSI by default on G72 (NV46) devices where it's >> apparently a bit buggy. We have a later patch which turns MSI back on >> with a quirk, but it isn't extremely necessary for these devices, and >> disabling (or, rather, not enabling) MSI is a pretty safe thing to do. >> >> The patch went upstream in 4.3-rc1, however I believe that there are >> still a number of kernels between 3.12 (where MSI was first enabled by >> default - commit a27e56996) and 4.2 (inclusive) which are still being >> maintained. To those maintainers, please consider including this in >> your trees. > > But it needs > commit fa8c9ac72fe0bcdf5bc7cc84e85cc2a1af53f9fd > Author: Ilia Mirkin <imirkin@xxxxxxxxxxxx> > Date: Wed Feb 5 14:33:02 2014 -0500 > > drm/nv4c/mc: nv4x igp's have a different msi rearm register > > See https://bugs.freedesktop.org/show_bug.cgi?id=74492 > > which is only in 3.14. So I cannot take it into 3.12. Doh! I could have sworn that this commit was also backported, but I guess not. I did a big more digging, a few results: (a) v3.12 didn't actually have MSI enabled by default. It got turned off in one of the rc's, and didn't get turned back on until v3.13. So Jiri, you're all good (for 3.12 at least). Sorry about the wrong version endpoints in my comment. (b) For 3.13 stable, if such a tree exists, it wouldn't hurt to then include both fa8c9ac72fe0bcdf5bc7cc84e85cc2a1af53f9fd as well as 4761703bd04bbdf56396d264903cc5a1fdcb3c01 (drm/nv4c/mc: disable msi) -- that one was, in fact, backported, but I guess only to 3.14. [And without that second one, the original commit wouldn't have the desired effect -- we want to disable MSI there, not actually flip it to the nv4c msi rearm method.] In case of tl;dr, my recommendation is to backport into 3.13: fa8c9ac72fe0bcdf5bc7cc84e85cc2a1af53f9fd 4761703bd04bbdf56396d264903cc5a1fdcb3c01 0a363e85cdafbceeee6a49b91c604d0d4d070dc7 In that order. This should avoid buggy MSI on the nv4x IGPs as well as NV46 (G72). Starting with v3.14, you should only need 0a363e85cdafbceeee6a49b91c604d0d4d070dc7, since presumably 4761703bd04bbdf56396d264903cc5a1fdcb3c01 will have already been backported. Cheers, -ilia -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html