[Intel-gfx] [PATCH 1/2] drm/i915: Fix modeset handling during gpu reset, v2.
Ville Syrjälä
ville.syrjala at linux.intel.com
Fri May 6 13:06:12 UTC 2016
On Mon, May 02, 2016 at 10:57:01AM +0200, Maarten Lankhorst wrote:
> This function would call drm_modeset_lock_all, while the suspend/resume
> functions already have their own locking. Fix this by factoring out
> __intel_display_resume, and calling the atomic helpers for duplicating
> atomic state and disabling all crtc's during suspend.
>
> Changes since v1:
> - Deal with -EDEADLK right after lock_all and clean up calls
> to hw readout.
> - Always take all modeset locks so updates during gpu reset are blocked.
Found this patch by accident. --in-reply-to would have helped a bit.
>
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Fixes: e2c8b8701e2d ("drm/i915: Use atomic helpers for suspend, v2.")
> Cc: drm-intel-fixes at lists.freedesktop.org
> ---
> drivers/gpu/drm/i915/intel_display.c | 141 ++++++++++++++++++++++-------------
> 1 file changed, 89 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 2f36414702fe..4fb904f2bcf9 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -3144,27 +3144,83 @@ static void intel_update_primary_planes(struct drm_device *dev)
> }
> }
>
> +static int
> +__intel_display_resume(struct drm_device *dev,
> + struct drm_atomic_state *state)
> +{
> + struct drm_crtc_state *crtc_state;
> + struct drm_crtc *crtc;
> + int i;
> +
> + intel_modeset_setup_hw_state(dev);
> + i915_redisable_vga(dev);
> +
> + if (!state)
> + return 0;
> +
> + for_each_crtc_in_state(state, crtc, crtc_state, i) {
> + /*
> + * Force recalculation even if we restore
> + * current state. With fast modeset this may not result
> + * in a modeset when the state is compatible.
> + */
> + crtc_state->mode_changed = true;
> + }
> +
> + return drm_atomic_commit(state);
The -EDEADLK warn could be here so we don't have to duplicate it in two
places perhaps? Extracting __intel_display_reset() could also be a separate
patch to make this stuff a bit easier to review.
Oh and BTW resume is also broken on platforms that have the force pipe A
quirk. I do have some patches lined up to nuke that quirk for good, which
I should probably post sooner rather than later. But those have at least
a theoretical chance of regressing something, so in the meantime I think
we'll still need to fix this thing for the normal resume path as well.
> +}
> +
> void intel_prepare_reset(struct drm_device *dev)
> {
> + struct drm_atomic_state *state;
> + struct drm_modeset_acquire_ctx *pctx;
> + struct drm_i915_private *dev_priv = to_i915(dev);
> + int ret;
> +
> /* no reset support for gen2 */
> - if (IS_GEN2(dev))
> + if (IS_GEN2(dev_priv))
> return;
>
> - /* reset doesn't touch the display */
> - if (INTEL_INFO(dev)->gen >= 5 || IS_G4X(dev))
> + drm_modeset_lock_all(dev);
Isn't that going to clash with the locking in
intel_update_primary_planes() ?
> +
> + /* reset doesn't touch the display, but flips might get nuked anyway, */
> + if (INTEL_INFO(dev_priv)->gen >= 5 || IS_G4X(dev_priv))
> return;
>
> - drm_modeset_lock_all(dev);
> + pctx = dev->mode_config.acquire_ctx;
Still looks like power context.
> +
> /*
> * Disabling the crtcs gracefully seems nicer. Also the
> * g33 docs say we should at least disable all the planes.
> */
> - intel_display_suspend(dev);
> +
> + state = drm_atomic_helper_duplicate_state(dev, pctx);
> + if (IS_ERR(state)) {
> + ret = PTR_ERR(state);
> + state = NULL;
> + DRM_ERROR("Duplicating state failed with %i\n", ret);
> + goto err;
> + }
> +
> + ret = drm_atomic_helper_disable_all(dev, pctx);
> + if (ret) {
> + DRM_ERROR("Suspending crtc's failed with %i\n", ret);
> + goto err;
> + }
> +
> + dev_priv->modeset_restore_state = state;
> + state->acquire_ctx = pctx;
> + return;
> +
> +err:
> + drm_atomic_state_free(state);
> }
>
> void intel_finish_reset(struct drm_device *dev)
> {
> struct drm_i915_private *dev_priv = to_i915(dev);
> + struct drm_atomic_state *state = dev_priv->modeset_restore_state;
> + int ret;
>
> /*
> * Flips in the rings will be nuked by the reset,
> @@ -3177,6 +3233,8 @@ void intel_finish_reset(struct drm_device *dev)
> if (IS_GEN2(dev))
> return;
>
> + dev_priv->modeset_restore_state = NULL;
> +
> /* reset doesn't touch the display */
> if (INTEL_INFO(dev)->gen >= 5 || IS_G4X(dev)) {
> /*
> @@ -3189,26 +3247,27 @@ void intel_finish_reset(struct drm_device *dev)
> * CS-based flips (which might get lost in gpu resets) any more.
> */
> intel_update_primary_planes(dev);
> - return;
> - }
> -
> - /*
> - * The display has been reset as well,
> - * so need a full re-initialization.
> - */
> - intel_runtime_pm_disable_interrupts(dev_priv);
> - intel_runtime_pm_enable_interrupts(dev_priv);
> + } else {
> + /*
> + * The display has been reset as well,
> + * so need a full re-initialization.
> + */
> + intel_runtime_pm_disable_interrupts(dev_priv);
> + intel_runtime_pm_enable_interrupts(dev_priv);
>
> - intel_modeset_init_hw(dev);
> + intel_modeset_init_hw(dev);
>
> - spin_lock_irq(&dev_priv->irq_lock);
> - if (dev_priv->display.hpd_irq_setup)
> - dev_priv->display.hpd_irq_setup(dev);
> - spin_unlock_irq(&dev_priv->irq_lock);
> + spin_lock_irq(&dev_priv->irq_lock);
> + if (dev_priv->display.hpd_irq_setup)
> + dev_priv->display.hpd_irq_setup(dev);
> + spin_unlock_irq(&dev_priv->irq_lock);
>
> - intel_display_resume(dev);
> + ret = __intel_display_resume(dev, state);
> + if (ret)
> + DRM_ERROR("Restoring old state failed with %i\n", ret);
>
> - intel_hpd_init(dev_priv);
> + intel_hpd_init(dev_priv);
> + }
>
> drm_modeset_unlock_all(dev);
> }
> @@ -15957,9 +16016,10 @@ void intel_display_resume(struct drm_device *dev)
> struct drm_atomic_state *state = dev_priv->modeset_restore_state;
> struct drm_modeset_acquire_ctx ctx;
> int ret;
> - bool setup = false;
>
> dev_priv->modeset_restore_state = NULL;
> + if (state)
> + state->acquire_ctx = &ctx;
>
> /*
> * This is a cludge because with real atomic modeset mode_config.mutex
> @@ -15970,40 +16030,17 @@ void intel_display_resume(struct drm_device *dev)
> mutex_lock(&dev->mode_config.mutex);
> drm_modeset_acquire_init(&ctx, 0);
>
> -retry:
> - ret = drm_modeset_lock_all_ctx(dev, &ctx);
> -
> - if (ret == 0 && !setup) {
> - setup = true;
> -
> - intel_modeset_setup_hw_state(dev);
> - i915_redisable_vga(dev);
> - }
> -
> - if (ret == 0 && state) {
> - struct drm_crtc_state *crtc_state;
> - struct drm_crtc *crtc;
> - int i;
> -
> - state->acquire_ctx = &ctx;
> -
> - for_each_crtc_in_state(state, crtc, crtc_state, i) {
> - /*
> - * Force recalculation even if we restore
> - * current state. With fast modeset this may not result
> - * in a modeset when the state is compatible.
> - */
> - crtc_state->mode_changed = true;
> - }
> -
> - ret = drm_atomic_commit(state);
> - }
> + while (1) {
> + ret = drm_modeset_lock_all_ctx(dev, &ctx);
> + if (ret != -EDEADLK)
> + break;
>
> - if (ret == -EDEADLK) {
> drm_modeset_backoff(&ctx);
> - goto retry;
> }
>
> + ret = __intel_display_resume(dev, state);
Shouldn't we skip this call if the lock_all failed?
> + WARN_ON(ret == -EDEADLK);
> +
> drm_modeset_drop_locks(&ctx);
> drm_modeset_acquire_fini(&ctx);
> mutex_unlock(&dev->mode_config.mutex);
> --
> 2.5.5
>
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--
Ville Syrjälä
Intel OTC
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