On 05.04.2018 11:49, Enric Balletbo i Serra wrote:
> From: Tomasz Figa <tf...@chromium.org>
>
> The first time after we call rockchip_drm_do_flush() after
> rockchip_drm_psr_register(), we go from PSR_DISABLE to PSR_FLUSH. The
> difference between PSR_DISABLE and PSR_FLUSH is whether or not we have a
> delayed work pending - PSR is off in either state.  However
> psr_set_state() only catches the transition from PSR_FLUSH to
> PSR_DISABLE (which never happens), while going from PSR_DISABLE to
> PSR_FLUSH triggers a call to psr->set() to disable PSR while it's
> already disabled. This triggers the eDP PHY power-on sequence without
> being shut down first and this seems to occasionally leave the encoder
> unable to later enable PSR. Let's just simplify the state machine and
> simply consider PSR_DISABLE and PSR_FLUSH the same state. This lets us
> represent the hardware state by a simple boolean called "enabled" and,
> while at it, rename the misleading "active" boolean to "inhibit", which
> represents the purpose much better.

This phrase has no corresponding part in the patch.

>
> Also, userspace can (and does) trigger the rockchip_drm_do_flush() path
> from drmModeDirtyFB() at any time, whether or the encoder is active. If
> no mode is set, we call into analogix_dp_psr_set() which returns -EINVAL
> because encoder->crtc is NULL. Avoid this by starting out with
> psr->allowed set to false.

ditto

>
> Signed-off-by: Kristian H. Kristensen <hoegsb...@chromium.org>
> Signed-off-by: Tomasz Figa <tf...@chromium.org>

Original author should be first, 1st line of the patch "From:...."
suggests it should be Tomasz.

Regards
Andrzej

> Signed-off-by: Thierry Escande <thierry.esca...@collabora.com>
> Signed-off-by: Enric Balletbo i Serra <enric.balle...@collabora.com>
> Tested-by: Marek Szyprowski <m.szyprow...@samsung.com>
> ---
>
>  drivers/gpu/drm/rockchip/rockchip_drm_psr.c | 79 
> +++++++++--------------------
>  1 file changed, 23 insertions(+), 56 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c 
> b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
> index c8655e625ba2..448c5fde241c 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
> @@ -22,19 +22,13 @@
>  
>  #define PSR_FLUSH_TIMEOUT_MS 100
>  
> -enum psr_state {
> -     PSR_FLUSH,
> -     PSR_ENABLE,
> -     PSR_DISABLE,
> -};
> -
>  struct psr_drv {
>       struct list_head        list;
>       struct drm_encoder      *encoder;
>  
>       struct mutex            lock;
>       bool                    active;
> -     enum psr_state          state;
> +     bool                    enabled;
>  
>       struct delayed_work     flush_work;
>       struct work_struct      disable_work;
> @@ -78,52 +72,22 @@ static struct psr_drv *find_psr_by_encoder(struct 
> drm_encoder *encoder)
>       return psr;
>  }
>  
> -static void psr_set_state_locked(struct psr_drv *psr, enum psr_state state)
> +static int psr_set_state_locked(struct psr_drv *psr, bool enable)
>  {
> -     /*
> -      * Allowed finite state machine:
> -      *
> -      *   PSR_ENABLE  < = = = = = >  PSR_FLUSH
> -      *       | ^                        |
> -      *       | |                        |
> -      *       v |                        |
> -      *   PSR_DISABLE < - - - - - - - - -
> -      */
> -     if (state == psr->state || !psr->active)
> -             return;
> -
> -     /* Already disabled in flush, change the state, but not the hardware */
> -     if (state == PSR_DISABLE && psr->state == PSR_FLUSH) {
> -             psr->state = state;
> -             return;
> -     }
> +     int ret;
>  
> -     /* Actually commit the state change to hardware */
> -     switch (state) {
> -     case PSR_ENABLE:
> -             if (psr->set(psr->encoder, true))
> -                     return;
> -             break;
> -
> -     case PSR_DISABLE:
> -     case PSR_FLUSH:
> -             if (psr->set(psr->encoder, false))
> -                     return;
> -             break;
> -
> -     default:
> -             pr_err("%s: Unknown state %d\n", __func__, state);
> -             return;
> -     }
> +     if (!psr->active)
> +             return -EINVAL;
>  
> -     psr->state = state;
> -}
> +     if (enable == psr->enabled)
> +             return 0;
>  
> -static void psr_set_state(struct psr_drv *psr, enum psr_state state)
> -{
> -     mutex_lock(&psr->lock);
> -     psr_set_state_locked(psr, state);
> -     mutex_unlock(&psr->lock);
> +     ret = psr->set(psr->encoder, enable);
> +     if (ret)
> +             return ret;
> +
> +     psr->enabled = enable;
> +     return 0;
>  }
>  
>  static void psr_flush_handler(struct work_struct *work)
> @@ -131,10 +95,8 @@ static void psr_flush_handler(struct work_struct *work)
>       struct psr_drv *psr = container_of(to_delayed_work(work),
>                                          struct psr_drv, flush_work);
>  
> -     /* If the state has changed since we initiated the flush, do nothing */
>       mutex_lock(&psr->lock);
> -     if (psr->state == PSR_FLUSH)
> -             psr_set_state_locked(psr, PSR_ENABLE);
> +     psr_set_state_locked(psr, true);
>       mutex_unlock(&psr->lock);
>  }
>  
> @@ -176,6 +138,7 @@ int rockchip_drm_psr_deactivate(struct drm_encoder 
> *encoder)
>  
>       mutex_lock(&psr->lock);
>       psr->active = false;
> +     psr->enabled = false;
>       mutex_unlock(&psr->lock);
>       cancel_delayed_work_sync(&psr->flush_work);
>       cancel_work_sync(&psr->disable_work);
> @@ -187,8 +150,12 @@ EXPORT_SYMBOL(rockchip_drm_psr_deactivate);
>  static void rockchip_drm_do_flush(struct psr_drv *psr)
>  {
>       cancel_delayed_work_sync(&psr->flush_work);
> -     psr_set_state(psr, PSR_FLUSH);
> -     mod_delayed_work(system_wq, &psr->flush_work, PSR_FLUSH_TIMEOUT_MS);
> +
> +     mutex_lock(&psr->lock);
> +     if (!psr_set_state_locked(psr, false))
> +             mod_delayed_work(system_wq, &psr->flush_work,
> +                              PSR_FLUSH_TIMEOUT_MS);
> +     mutex_unlock(&psr->lock);
>  }
>  
>  /**
> @@ -355,8 +322,8 @@ int rockchip_drm_psr_register(struct drm_encoder *encoder,
>       INIT_WORK(&psr->disable_work, psr_disable_handler);
>       mutex_init(&psr->lock);
>  
> -     psr->active = true;
> -     psr->state = PSR_DISABLE;
> +     psr->active = false;
> +     psr->enabled = false;
>       psr->encoder = encoder;
>       psr->set = psr_set;
>  


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