Re: [PATCH v3 3/6] drm/bridge: analogix_dp: detect Sink PSR state after configuring the PSR

From: Sean Paul
Date: Tue Oct 18 2016 - 11:53:30 EST

On Tue, Oct 18, 2016 at 2:21 AM, Zain Wang <wzz@xxxxxxxxxxxxxx> wrote:
> From: Yakir Yang <ykk@xxxxxxxxxxxxxx>
>
> Make sure the request PSR state takes effect in analogix_dp_send_psr_spd()
> function, or print the sink PSR error state if we failed to apply the
> requested PSR setting.
>
> Signed-off-by: zain wang <wzz@xxxxxxxxxxxxxx>
> Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
> ---
>
> Changes in v3: None
> Changes in v2: None
>
> drivers/gpu/drm/bridge/analogix/analogix_dp_core.c | 6 ++----
> drivers/gpu/drm/bridge/analogix/analogix_dp_core.h | 6 ++++--
> drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c | 25 ++++++++++++++++++++--
> drivers/gpu/drm/rockchip/analogix_dp-rockchip.c | 6 ++++--
> 4 files changed, 33 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> index bcae4dd..7faad93 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
> @@ -124,8 +124,7 @@ int analogix_dp_enable_psr(struct device *dev)
> psr_vsc.DB0 = 0;
> psr_vsc.DB1 = EDP_VSC_PSR_STATE_ACTIVE | EDP_VSC_PSR_CRC_VALUES_VALID;
>
> - analogix_dp_send_psr_spd(dp, &psr_vsc);
> - return 0;
> + return analogix_dp_send_psr_spd(dp, &psr_vsc);
> }
> EXPORT_SYMBOL_GPL(analogix_dp_enable_psr);
>
> @@ -147,8 +146,7 @@ int analogix_dp_disable_psr(struct device *dev)
> psr_vsc.DB0 = 0;
> psr_vsc.DB1 = 0;
>
> - analogix_dp_send_psr_spd(dp, &psr_vsc);
> - return 0;
> + return analogix_dp_send_psr_spd(dp, &psr_vsc);
> }
> EXPORT_SYMBOL_GPL(analogix_dp_disable_psr);
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> index 5c6a288..cdc0535 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
> @@ -20,6 +20,8 @@
> #define MAX_CR_LOOP 5
> #define MAX_EQ_LOOP 5
>
> +#define DP_TIMEOUT_PSR_LOOP_MS msecs_to_jiffies(300)

This value isn't MS units, it's jiffies.

> +
> /* DP_MAX_LANE_COUNT */
> #define DPCD_ENHANCED_FRAME_CAP(x) (((x) >> 7) & 0x1)
> #define DPCD_MAX_LANE_COUNT(x) ((x) & 0x1f)
> @@ -247,8 +249,8 @@ void analogix_dp_config_video_slave_mode(struct analogix_dp_device *dp);
> void analogix_dp_enable_scrambling(struct analogix_dp_device *dp);
> void analogix_dp_disable_scrambling(struct analogix_dp_device *dp);
> void analogix_dp_enable_psr_crc(struct analogix_dp_device *dp);
> -void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> - struct edp_vsc_psr *vsc);
> +int analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> + struct edp_vsc_psr *vsc);
> ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
> struct drm_dp_aux_msg *msg);
>
> diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> index cd37ac0..9e1177c 100644
> --- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> +++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
> @@ -992,10 +992,12 @@ void analogix_dp_enable_psr_crc(struct analogix_dp_device *dp)
> writel(PSR_VID_CRC_ENABLE, dp->reg_base + ANALOGIX_DP_CRC_CON);
> }
>
> -void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> - struct edp_vsc_psr *vsc)
> +int analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> + struct edp_vsc_psr *vsc)
> {
> + unsigned long timeout;
> unsigned int val;
> + u8 sink;
>
> /* don't send info frame */
> val = readl(dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
> @@ -1036,6 +1038,25 @@ void analogix_dp_send_psr_spd(struct analogix_dp_device *dp,
> val = readl(dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
> val |= IF_EN;
> writel(val, dp->reg_base + ANALOGIX_DP_PKT_SEND_CTL);
> +
> + timeout = jiffies + DP_TIMEOUT_PSR_LOOP_MS;
> + while (time_before(jiffies, timeout)) {
> + val = drm_dp_dpcd_readb(&dp->aux, DP_PSR_STATUS, &sink);
> + if (val != 1) {
> + dev_err(dp->dev, "PSR_STATUS read failed ret=%d", val);
> + return -EBUSY;
> + }
> +
> + if ((vsc->DB1 && sink == DP_PSR_SINK_ACTIVE_RFB) ||
> + (!vsc->DB1 && sink == DP_PSR_SINK_INACTIVE))
> + return 0;
> +
> + usleep_range(1000, 1500);
> + }
> +
> + dev_warn(dp->dev, "Failed to apply PSR, sink state was [%x]", sink);
> +
> + return -ETIMEDOUT;


This can all be replaced with readx_poll_timeout

> }
>
> ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
> diff --git a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> index e5471e7..1c2d756 100644
> --- a/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> +++ b/drivers/gpu/drm/rockchip/analogix_dp-rockchip.c
> @@ -105,7 +105,7 @@ static void analogix_dp_psr_work(struct work_struct *work)
> struct rockchip_dp_device *dp =
> container_of(work, typeof(*dp), psr_work);
> struct drm_crtc *crtc = dp->encoder.crtc;
> - int psr_state = dp->psr_state;
> + int psr_state;
> int vact_end;
> int ret;
> unsigned long flags;
> @@ -123,11 +123,13 @@ static void analogix_dp_psr_work(struct work_struct *work)
> }
>
> spin_lock_irqsave(&dp->psr_lock, flags);
> + psr_state = dp->psr_state;
> + spin_unlock_irqrestore(&dp->psr_lock, flags);
> +
> if (psr_state == EDP_VSC_PSR_STATE_ACTIVE)
> analogix_dp_enable_psr(dp->dev);
> else
> analogix_dp_disable_psr(dp->dev);
> - spin_unlock_irqrestore(&dp->psr_lock, flags);

I think we've been back and forth on this enough times to know what
I'm going to say about moving/removing the lock here :-)

It seems like the reason you need to do this is because of the
proliferation of spinlocks through the psr stack (which I think is due
to the way flush timer is implemented).

I just whipped up a patch to change this stuff to non-atomic context
such that we can keep locking things in a safe manner. I'll post it on
list and cc you, you can then rebase your set on that.

Sean



> }
>
> static int rockchip_dp_pre_init(struct rockchip_dp_device *dp)
> --
> 1.9.1
>
>
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