Re: [PATCH] drm/rockchip: cdn-dp: Fix error handling

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On 2017年02月20日 14:41, Christophe JAILLET wrote:
Le 20/02/2017 à 02:40, Mark yao a écrit :
On 2017年02月20日 00:59, Christophe JAILLET wrote:
It is likely that both 'clk_disable_unprepare()' should be called if
'pm_runtime_get_sync()' fails.

Add a new label for that, because 'err_set_rate' is not meaningful in this
case.


Fixes: 1a0f7ed3abe2 ("drm/rockchip: cdn-dp: add cdn DP support for rk3399")

Signed-off-by: Christophe JAILLET <christophe.jaillet@xxxxxxxxxx>
---
Not sure but a 'pm_runtime_get_sync()' is maybe also required in the
'err_set_rate' path.
---
  drivers/gpu/drm/rockchip/cdn-dp-core.c | 3 ++-
  1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/rockchip/cdn-dp-core.c b/drivers/gpu/drm/rockchip/cdn-dp-core.c
index 9ab67a670885..0fe1ec8b8fb1 100644
--- a/drivers/gpu/drm/rockchip/cdn-dp-core.c
+++ b/drivers/gpu/drm/rockchip/cdn-dp-core.c
@@ -111,7 +111,7 @@ static int cdn_dp_clk_enable(struct cdn_dp_device *dp)
      ret = pm_runtime_get_sync(dp->dev);
      if (ret < 0) {
          DRM_DEV_ERROR(dp->dev, "cannot get pm runtime %d\n", ret);
-        goto err_pclk;
+        goto err_sync;

I think the name err_pm_runtime_get is better.
err_sync is not a clear name for the pm_runtime_get_sync.

I will change it.

      }
        reset_control_assert(dp->core_rst);
@@ -133,6 +133,7 @@ static int cdn_dp_clk_enable(struct cdn_dp_device *dp)
      return 0;
    err_set_rate:
+err_sync:

miss pm_runtime_put, it should be:

I am wondering if 'pm_runtime_put_sync' should be added, instead.
We want to revert the 'pm_runtime_get_sync' of line 111. According to the naming of the function, the _sync version looks more logical to me. Using ccoccinelle shows that 2/3 of functions calling both 'pm_runtime_get_sync' and 'pm_runtime_get[_sync]' and using the _sync variant.


pm_runtime_get_sync will block until hardware actually done power configure,
we need make sure power is enable before use the hardware, So we should use pm_runtime_get_sync at power on.

At power off time, use pm_runtime_put is enough, it can be async, no need block.

Thanks.

Which semantic is the correct one?


err_set_rate:
    pm_runtime_put(dp->dev);
err_pm_runtime_get:
    clk_disable_unprepare(dp->core_clk);
err_core_clk:

clk_disable_unprepare(dp->core_clk);
  err_core_clk:
      clk_disable_unprepare(dp->pclk);








--
Mark Yao


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