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

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Hi Sean,

On 09/12/2016 09:52 PM, Sean Paul wrote:
On Fri, Sep 9, 2016 at 5:45 AM, Yakir Yang <ykk@xxxxxxxxxxxxxx> wrote:
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: Yakir Yang <ykk@xxxxxxxxxxxxxx>
---
Changes in v3:
- Update commit message
- Add DP_TIMEOUT_PSR_LOOP_MS marcos
- Correct the return values of analogix_dp_send_psr_spd()

Changes in v2:
- A bunch of good fixes from Sean

  drivers/gpu/drm/bridge/analogix/analogix_dp_core.c |  6 ++----
  drivers/gpu/drm/bridge/analogix/analogix_dp_core.h |  5 +++--
  drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c  | 25 ++++++++++++++++++++--
  3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index 5fe3982..c0ce16a 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -116,8 +116,7 @@ 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);

@@ -139,8 +138,7 @@ 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 d564e90..a27f1e3 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.h
@@ -20,6 +20,7 @@
  #define MAX_EQ_LOOP 5

  #define DP_TIMEOUT_LOOP_MS                     msecs_to_jiffies(1)
+#define DP_TIMEOUT_PSR_LOOP_MS                 msecs_to_jiffies(300)
Same comment here re: units.

300ms seems like a really long time. Why does it take this long?

This magic number '300ms' just come from my test, I haven't found the description in eDP 1.4a Spec about what exact time should Sink take to entry PSR.

- Yakir

Sean


  /* DP_MAX_LANE_COUNT */
  #define DPCD_ENHANCED_FRAME_CAP(x)             (((x) >> 7) & 0x1)
@@ -248,8 +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);
  #endif /* _ANALOGIX_DP_CORE_H */
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
index 15a4cf0..7fd4ed0 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_reg.c
@@ -1004,10 +1004,12 @@ 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);
@@ -1048,6 +1050,25 @@ 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;
  }

  ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
--
1.9.1


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