Re: [RFC PATCH 09/18] drm/i915: Cloned mode check

Daniel Vetter
2015-06-26T17:05:52Z

On Fri, Jun 26, 2015 at 07:21:53PM +0530, Ramalingam C wrote:
> If crtc is in clone mode, DRRS will be disabled. Because if the both
> the displays are not sharing the same vrefresh, then userspace
> activities based on vsync will go for toss.
>
> Clone mode will be rechecked on every restarting Idleness DRRS events.
>
> Signed-off-by: Ramalingam C <ramalingam.c@intel.com>
> ---
> drivers/gpu/drm/i915/intel_drrs.c | 36 +++++++++++++++++++++++++++++++++++-
> 1 file changed, 35 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_drrs.c b/drivers/gpu/drm/i915/intel_drrs.c
> index e5d8bcd..42b420d 100644
> --- a/drivers/gpu/drm/i915/intel_drrs.c
> +++ b/drivers/gpu/drm/i915/intel_drrs.c
> @@ -16,6 +16,7 @@
>
> #include <drm/i915_drm.h>
> #include <linux/delay.h>
> +#include <linux/list.h>
>
> #include "i915_drv.h"
> #include "intel_drv.h"
> @@ -85,6 +86,31 @@ int get_free_drrs_struct_index(struct drm_i915_private *dev_priv)
> return -EBUSY;
> }
>
> +/*
> + * TODO: This is identifying the multiple active crtcs at a time.
> + * Here we assume that this is clone state and disable DRRS.
> + * But need to implement a proper method to find the real cloned mode
> + * state. DRRS need not be disabled incase of multiple crtcs with
> + * different content.
> + */

This is a pretty big hack. Why do you need it? fb tracking should keep any
display in the high mode as long as there's activity, so as long as
userspace flips both buffers for both pipes (which is should for cloned
mode) they'll both be running at max.

And for non-cloned mode (e.g. video only on external TV) things will be
controlled independantly.

Smells a lot like trying to encode policy instead of making sure that the
resulting behaviour matches what we want. And I think it should already.
-Daniel

> +
> +bool is_cloned_mode_active(struct drm_device *dev)
> +{
> + struct drm_crtc *crtc = NULL, *tmp_crtc;
> +
> + list_for_each_entry(tmp_crtc, &dev->mode_config.crtc_list, head) {
> + if (crtc && intel_crtc_active(tmp_crtc)) {
> + DRM_DEBUG_KMS(
> + "more than one crtc active. Declared as clonec mode\n");
> + return true;
> + }
> +
> + if (intel_crtc_active(tmp_crtc))
> + crtc = tmp_crtc;
> + }
> + return false;
> +}
> +
> void intel_set_drrs_state(struct i915_drrs *drrs)
> {
> struct drrs_info *drrs_state;
> @@ -158,7 +184,10 @@ static void intel_idleness_drrs_work_fn(struct work_struct *__work)
>
> panel = &drrs->connector->panel;
>
> - /* TODO: If DRRS is not supported on clone mode act here */
> + /* Double check if the dual-display mode is active. */
> + if (drrs->is_clone)
> + return;
> +
> mutex_lock(&drrs->drrs_mutex);
> if (panel->target_mode != NULL)
> DRM_ERROR("FIXME: We shouldn't be here\n");
> @@ -192,6 +221,11 @@ static void intel_enable_idleness_drrs(struct i915_drrs *drrs)
>
> mutex_lock(&drrs->drrs_mutex);
>
> + drrs->is_clone = is_cloned_mode_active(drrs->connector->base.dev);
> +
> + if (drrs->is_clone)
> + return;
> +
> /* Capturing the deferred request for disable_drrs */
> if (drrs->drrs_state.type == SEAMLESS_DRRS_SUPPORT_SW &&
> drrs->encoder_ops->is_drrs_hr_state_pending) {
> --
> 1.7.9.5
>
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--
Daniel Vetter
Software Engineer, Intel Corporation