On Tue, Jul 09, 2013 at 01:14:09PM -0700, Guenter Roeck wrote:
> This reverts commit 36ec8f877481449bdfa072e6adf2060869e2b970.
>
> The commit results in repeated 'Timed out waiting for forcewake old ack
> to clear' messages on a Supermicro C7H61 board (BIOS version 2.00 and 2.00b)
> with i7-3770K CPU. It ultimately results in a hangup if the system is highly
> loaded. Reverting the commit fixes the issue.
>
> While I understand that this should be fixed in the BIOS, a more recent BIOS
> is not available fron the vendor. If/since no better solution is not available,
> reverting the patch seems to be the way to go (otherwise me and others with
> the same problem won't be able to run the upstream kernel on affected boards).
>
> Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
> Cc: Daniel Vetter <daniel.vetter@xxxxxxxx>
> Cc: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Can you please add the bugzilla link here?
> ---
> drivers/gpu/drm/i915/intel_pm.c | 31 +++++++++++++++++++++++++++----
> 1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index aa01128..5bae9ba 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4510,12 +4510,35 @@ void intel_gt_init(struct drm_device *dev)
> if (IS_VALLEYVIEW(dev)) {
> dev_priv->gt.force_wake_get = vlv_force_wake_get;
> dev_priv->gt.force_wake_put = vlv_force_wake_put;
> - } else if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) {
> - dev_priv->gt.force_wake_get = __gen6_gt_force_wake_mt_get;
> - dev_priv->gt.force_wake_put = __gen6_gt_force_wake_mt_put;
Please keep the unconditional use of mt forcewake for haswell, afaik we
don't have any reports that there are still broken BIOS out there.
> - } else if (IS_GEN6(dev)) {
> + } else if (INTEL_INFO(dev)->gen >= 6) {
> dev_priv->gt.force_wake_get = __gen6_gt_force_wake_get;
> dev_priv->gt.force_wake_put = __gen6_gt_force_wake_put;
> +
> + /* IVB configs may use multi-threaded forcewake */
> + if (IS_IVYBRIDGE(dev) || IS_HASWELL(dev)) {
> + u32 ecobus;
> +
> + /* A small trick here - if the bios hasn't configured
> + * MT forcewake, and if the device is in RC6, then
> + * force_wake_mt_get will not wake the device and the
> + * ECOBUS read will return zero. Which will be
> + * (correctly) interpreted by the test below as MT
> + * forcewake being disabled.
> + */
> + mutex_lock(&dev->struct_mutex);
> + __gen6_gt_force_wake_mt_get(dev_priv);
> + ecobus = I915_READ_NOTRACE(ECOBUS);
> + __gen6_gt_force_wake_mt_put(dev_priv);
> + mutex_unlock(&dev->struct_mutex);
> +
> + if (ecobus & FORCEWAKE_MT_ENABLE) {
> + DRM_DEBUG_KMS("Using MT version of forcewake\n");
> + dev_priv->gt.force_wake_get =
> + __gen6_gt_force_wake_mt_get;
> + dev_priv->gt.force_wake_put =
> + __gen6_gt_force_wake_mt_put;
> + }
This needs a DRM_INFO warning if MT forcewake is not available telling the
user telling the user that this might result in hangs with recent DDX
version, e.g.: "No MT forcewake available on Ivybridge, this can result in
issues when using vblank-synced partial screen updates."
Thanks, Daniel
> + }
> }
> INIT_DELAYED_WORK(&dev_priv->rps.delayed_resume_work,
> intel_gen6_powersave_work);
> --
> 1.7.9.7
>
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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