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  1. 10 Oct, 2013 22 commits
  3. 04 Oct, 2013 3 commits
  5. 03 Oct, 2013 5 commits
    • Chris Wilson's avatar
      drm/i915: Boost RPS frequency for CPU stalls · b29c19b6
      Chris Wilson authored 
      
If we encounter a situation where the CPU blocks waiting for results
from the GPU, give the GPU a kick to boost its the frequency.

This should work to reduce user interface stalls and to quickly promote
mesa to high frequencies - but the cost is that our requested frequency
stalls high (as we do not idle for long enough before rc6 to start
reducing frequencies, nor are we aggressive at down clocking an
underused GPU). However, this should be mitigated by rc6 itself powering
off the GPU when idle, and that energy use is dependent upon the workload
of the GPU in addition to its frequency (e.g. the math or sampler
functions only consume power when used). Still, this is likely to
adversely affect light workloads.

In particular, this nearly eliminates the highly noticeable wake-up lag
in animations from idle. For example, expose or workspace transitions.
(However, given the situation where we fail to downclock, our requested
frequency is almost always the maximum, except for Baytrail where we
manually downclock upon idling. This often masks the latency of
upclocking after being idle, so animations are typically smooth - at the
cost of increased power consumption.)

Stéphane raised the concern that this will punish good applications and
reward bad applications - but due to the nature of how mesa performs its
client throttling, I believe all mesa applications will be roughly
equally affected. To address this concern, and to prevent applications
like compositors from permanently boosting the RPS state, we ratelimit the
frequency of the wait-boosts each client recieves.

Unfortunately, this techinique is ineffective with Ironlake - which also
has dynamic render power states and suffers just as dramatically. For
Ironlake, the thermal/power headroom is shared with the CPU through
Intelligent Power Sharing and the intel-ips module. This leaves us with
no GPU boost frequencies available when coming out of idle, and due to
hardware limitations we cannot change the arbitration between the CPU and
GPU quickly enough to be effective.

v2: Limit each client to receiving a single boost for each active period.
    Tested by QA to only marginally increase power, and to demonstrably
    increase throughput in games. No latency measurements yet.

v3: Cater for front-buffer rendering with manual throttling.

v4: Tidy up.

v5: Sadly the compositor needs frequent boosts as it may never idle, but
due to its picking mechanism (using ReadPixels) may require frequent
waits. Those waits, along with the waits for the vrefresh swap, conspire
to keep the GPU at low frequencies despite the interactive latency. To
overcome this we ditch the one-boost-per-active-period and just ratelimit
the number of wait-boosts each client can receive.
Reported-and-tested-by: default avatarPaul Neumann <paul104x@yahoo.de>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=68716

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Kenneth Graunke <kenneth@whitecape.org>
Cc: Stéphane Marchesin <stephane.marchesin@gmail.com>
Cc: Owen Taylor <otaylor@redhat.com>
Cc: "Meng, Mengmeng" <mengmeng.meng@intel.com>
Cc: "Zhuang, Lena" <lena.zhuang@intel.com>
Reviewed-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
[danvet: No extern for function prototypes in headers.]
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      b29c19b6
    • Ville Syrjälä's avatar
      drm/i915: Don't populate pipe_src_{w,h} multiple times · e41a56be
      Ville Syrjälä authored 
      
If we ever end up doing the retry loop due to bandwidth constraints, we
would rewrite pipe_src_{w,n} based on adjusted_mode timings. But by that
time the encoder may have already replaced the adjusted_mode with a
fixed panel mode, which would then corrupt pipe_src_{w,h}.

v2: Use requested_mode and slap on a big comment from Daniel
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      e41a56be
    • Paulo Zanoni's avatar
      drm/i915: implement the Haswell mode set sequence workaround · e4916946
      Paulo Zanoni authored 
      
This workaround is described in the mode set sequence documentation.
When enabling planes for the second pipe, we need to wait for 2
vblanks on the first pipe. This should solve "a flash of screen
corruption if planes are enabled on second/third pipe during the time
that big FIFO mode is exiting". Watermarks are fun :)

v2: Save indentation levels
Signed-off-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      e4916946
    • Ville Syrjälä's avatar
      drm/i915: Disable/enable planes as the first/last thing during modeset on HSW · dda9a66a
      Ville Syrjälä authored 
      
Refactor the plane enabling/disabling into helper functions and move
the calls to happen as the first thing during .crtc_disable, and the
last thing during .crtc_enable.

Those are the two clear points where we are sure that the pipe is
actually running regardless of the encoder type or hardware
generation.

v2: Made by Paulo:
  Remove the code touching everything but the Haswell functions. We
  need this change on Haswell right now since it fixes a FIFO underrun
  that we get on pipe A while we enable pipe B (see the workaround
  notes on the Haswell mode set sequence documentation). We can bring
  back the code to gens 2-7 later, once they're tested.
Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: default avatarPaulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      dda9a66a
    • Jesse Barnes's avatar
      i915/vlv: untangle integrated clock source handling v4 · f6071166
      Jesse Barnes authored 
      The global integrated clock source bit resides in DPLL B on VLV, but we
were treating it as a per-pipe resource.  It needs to be set whenever
any PLL is active, so pull setting the bit out of vlv_update_pll and
into vlv_enable_pll.  Also add a vlv_disable_pll to prevent disabling it
when pipe B shuts down.

I'm guessing on the references here, I expect this to bite any config
where multiple displays are active or displays are moved from pipe to
pipe.

v2: re-add bits in vlv_update_pll to keep from confusing the state checker
v3: use enum pipe checks (Daniel)
    set CRI clock source early (Ville)
    consistently set CRI clock source everywhere (Ville)
v4: drop unnecessary setting of bit in vlv enable pll (Ville)

References: https://bugs.freedesktop.org/show_bug.cgi?id=67245
References: https://bugs.freedesktop.org/show_bug.cgi?id=69693

Signed-off-by: default avatarJesse Barnes <jbarnes@virtuousgeek.org>
Reviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: s/1/PIPE_B/]
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      f6071166
  7. 01 Oct, 2013 10 commits

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