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Commit 0cd1262d authored by Matt Roper's avatar Matt Roper
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drm/i915: Handle error paths during watermark sanitization properly (v3) 



sanitize_watermarks() does not properly handle errors returned by
drm_atomic_helper_duplicate_state().  Make failures drop locks before
returning.  We also change the lock of connection_mutex to a
drm_modeset_lock_all_ctx() to make sure any EDEADLK's are handled
earlier.

v2: Change call to lock connetion_mutex with a call to
    drm_modeset_lock_all_ctx().  This ensures that any lock contention
    is handled earlier and drm_atomic_helper_duplicate_state() won't
    return EDEADLK. (Maarten)

v3: Drop locks properly in more error paths. (Maarten)

Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Signed-off-by: default avatarMatt Roper <matthew.d.roper@intel.com>
Reviewed-by: default avatarMaarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1452611617-32144-1-git-send-email-matthew.d.roper@intel.com
parent ceccad59

drivers/gpu/drm/i915/intel_display.c

+5 −4
Original line number Diff line number Diff line
@@ -15355,17 +15355,17 @@ static void sanitize_watermarks(struct drm_device *dev) 
	 */

	drm_modeset_acquire_init(&ctx, 0);

retry:

	ret = drm_modeset_lock(&dev->mode_config.connection_mutex, &ctx);

	ret = drm_modeset_lock_all_ctx(dev, &ctx);

	if (ret == -EDEADLK) {

		drm_modeset_backoff(&ctx);

		goto retry;

	} else if (WARN_ON(ret)) {

		return;

		goto fail;

	}



	state = drm_atomic_helper_duplicate_state(dev, &ctx);

	if (WARN_ON(IS_ERR(state)))

		return;

		goto fail;



	/*

	 * Hardware readout is the only time we don't want to calculate
@@ -15388,7 +15388,7 @@ static void sanitize_watermarks(struct drm_device *dev) 
		 * BIOS-programmed watermarks untouched and hope for the best.

		 */

		WARN(true, "Could not determine valid watermarks for inherited state\n");

		return;

		goto fail;

	}



	/* Write calculated watermark values back */
@@ -15401,6 +15401,7 @@ static void sanitize_watermarks(struct drm_device *dev) 
	}



	drm_atomic_state_free(state);

fail:

	drm_modeset_drop_locks(&ctx);

	drm_modeset_acquire_fini(&ctx);

}