On Tue, Mar 29, 2016 at 12:49 AM, Andy Lutomirski luto@amacapital.net wrote:
On Tue, Mar 29, 2016 at 12:43 AM, Daniel Vetter daniel.vetter@ffwll.ch wrote:
On Tue, Mar 29, 2016 at 4:39 AM, Andy Lutomirski luto@amacapital.net wrote:
AFAICT something got rather screwed up in i915 land for 4.5.
$ git log --oneline --grep='Pretend cursor is always on' v4.5 drivers/gpu/drm/i915/ e2e407dc093f drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2)
$ git log --oneline --grep='Pretend cursor is always on' v4.6-rc1 drivers/gpu/drm/i915/ e2e407dc093f drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2) b2435692dbb7 drm/i915: Pretend cursor is always on for ILK-style WM calculations (v2)
The two patches there are almost, but not quite, the same thing, which makes me wonder how they both ended up in Linus' tree without an obvious merge conflict.
I have no idea what caused this. However, I think (on very little inspection, but it's consistent with problems I have with 4.5 on my laptop) that the first one is an *incorrect* fix for a regression in 4.5 and the second is a correct fix for the same regression. 4.6-rc1 seems okay.
I reported the regression and everyone involved has known about it for weeks. Nonetheless, 4.5 final is busted.
Quoting from e2e407dc093f
"(cherry picked from commit b2435692dbb709d4c8ff3b2f2815c9b8423b72bb)"
i.e. this is intentionally twice in the history. We started to soak bugfixes in -next and then cherry pick them because we had too much fun with things blowing up, and also too much fun with really messy conflicts. It's not a botched patch in 4.5 or anything else nefarious at all.
Bah, sorry, I read it wrong. They have the same final state but they were on different bases. I somehow reversed this in my head and thought they had the same initial state and different final states.
Also, sorry for the excessive diatribe. I plead sleepiness and mis-reading of code.
--Andy