Re: [PATCH v2 4/6] drm/rockchip: A couple small fixes to psr

From: Yakir Yang <ykk@rock-chips.com>
To: Sean Paul <seanpaul@chromium.org>,
	mark.yao@rock-chips.com, dri-devel@lists.freedesktop.org
Cc: marcheu@chromium.org, dianders@chromium.org,
	linux-rockchip@lists.infradead.org
Subject: Re: [PATCH v2 4/6] drm/rockchip: A couple small fixes to psr
Date: Wed, 17 Aug 2016 10:34:46 +0800	[thread overview]
Message-ID: <03d77274-1ada-9fc8-00ef-3f2af9da6d00@rock-chips.com> (raw)
In-Reply-To: <1471396276-8222-5-git-send-email-seanpaul@chromium.org>


On 08/17/2016 09:11 AM, Sean Paul wrote:
> A few things that need tidying up, no functional changes.
>
> Signed-off-by: Sean Paul <seanpaul@chromium.org>
Reviewed-by: Yakir Yang <ykk@rock-chips.com>
> ---
>
> Changes in v2:
> 	- Introduced
>
>   drivers/gpu/drm/rockchip/rockchip_drm_psr.c | 19 +++++++------------
>   1 file changed, 7 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
> index 5bd54f2..c6ac5d0 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
> @@ -62,27 +62,25 @@ static void psr_set_state_locked(struct psr_drv *psr, enum psr_state state)
>   	 * Allowed finite state machine:
>   	 *
>   	 *   PSR_ENABLE  < = = = = = >  PSR_FLUSH
> -	  *      | ^                        |
> -	  *      | |                        |
> -	  *      v |                        |
> +	 *       | ^                        |
> +	 *       | |                        |
> +	 *       v |                        |
>   	 *   PSR_DISABLE < - - - - - - - - -
>   	 */
> -
> -	/* Forbid no state change */
>   	if (state == psr->state)
>   		return;
>   
> -	/* Forbid DISABLE change to FLUSH */
> +	/* Requesting a flush when disabled is a noop */
>   	if (state == PSR_FLUSH && psr->state == PSR_DISABLE)
>   		return;
>   
>   	psr->state = state;
>   
> -	/* Allow but no need hardware change, just need assign the state */
> +	/* Already disabled in flush, change the state, but not the hardware */
>   	if (state == PSR_DISABLE && psr->state == PSR_FLUSH)
>   		return;
>   
> -	/* Refact to hardware state change */
> +	/* Actually commit the state change to hardware */
>   	switch (psr->state) {
>   	case PSR_ENABLE:
>   		psr->set(psr->encoder, true);
> @@ -109,10 +107,7 @@ static void psr_flush_handler(unsigned long data)
>   	struct psr_drv *psr = (struct psr_drv *)data;
>   	unsigned long flags;
>   
> -	if (!psr)
> -		return;
> -
> -	/* State changed between flush time, then keep it */
> +	/* If the state has changed since we initiated the flush, do nothing */
>   	spin_lock_irqsave(&psr->lock, flags);
>   	if (psr->state == PSR_FLUSH)
>   		psr_set_state_locked(psr, PSR_ENABLE);


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