On Tue, Nov 29, 2016 at 09:40:29PM +0200, Imre Deak wrote:
> For LSPCON initialization during system resume we need AUX
> functionality, but we call the corresponding encoder reset hook with all
> interrupts disabled. Without interrupts we'll do a poll-wait for AUX
> transfer completions, which adds a significant delay if the transfers
> timeout/need to be retried for some reason.
>
> Fix this by enabling interrupts before calling the reset hooks. Note
> that while this will enable AUX interrupts it will keep HPD interrupts
> disabled, in a similar way to the init time output setup code.
>
> This issue existed since LSPCON support was added.
>
> v2:
> - Rebased on drm-tip.
>
> Cc: Shashank Sharma <shashank.sharma@xxxxxxxxx>
> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_drv.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index 8dac298..2cea2ef 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1582,18 +1582,21 @@ static int i915_drm_resume(struct drm_device *dev)
> intel_opregion_setup(dev_priv);
>
> intel_init_pch_refclk(dev_priv);
> - drm_mode_config_reset(dev);
>
> /*
> * Interrupts have to be enabled before any batches are run. If not the
> * GPU will hang. i915_gem_init_hw() will initiate batches to
> * update/restore the context.
> *
> + * drm_mode_config_reset() needs AUX interrupts.
> + *
> * Modeset enabling in intel_modeset_init_hw() also needs working
> * interrupts.
> */
> intel_runtime_pm_enable_interrupts(dev_priv);
>
> + drm_mode_config_reset(dev);
> +
Didn't look like anything should seriously explode.
Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
There is a slight concern on g4x/vlv/chv that an AUX interrupts would
trigger the hpd irq handler, which doesn't realize it's supposed to
ignore the actual hpd bits in PORT_HOTPLUG_STAT. So any aux before we
enable hpd processing for real could do something bad. So I guess we
should add some kind of software tracking for that stuff like we have
for PIPESTAT.
> mutex_lock(&dev->struct_mutex);
> if (i915_gem_init_hw(dev)) {
> DRM_ERROR("failed to re-initialize GPU, declaring wedged!\n");
> --
> 2.5.0
>
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--
Ville Syrjälä
Intel OTC
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