Thread (73 messages) 73 messages, 9 authors, 2021-09-13

Re: [PATCH 08/25] media: atmel: properly get pm_runtime

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Date: 2021-09-06 08:05:06
Also in: linux-arm-kernel, lkml

Hi Eugen,

Em Thu, 10 Jun 2021 12:00:42 +0000
[off-list ref] escreveu:
On 6/10/21 12:38 PM, Mauro Carvalho Chehab wrote:
quoted
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Em Thu, 10 Jun 2021 09:04:07 +0000
[off-list ref] escreveu:
  
quoted
quoted
quoted
diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c
index fe3ec8d0eaee..ce8e1351fa53 100644
--- a/drivers/media/platform/atmel/atmel-isc-base.c
+++ b/drivers/media/platform/atmel/atmel-isc-base.c
@@ -294,9 +294,13 @@ static int isc_wait_clk_stable(struct clk_hw *hw)
   static int isc_clk_prepare(struct clk_hw *hw)
   {
        struct isc_clk *isc_clk = to_isc_clk(hw);
+     int ret;

-     if (isc_clk->id == ISC_ISPCK)
-             pm_runtime_get_sync(isc_clk->dev);
+     if (isc_clk->id == ISC_ISPCK) {
+             ret = pm_runtime_resume_and_get(isc_clk->dev);
+             if (ret < 0)
+                     return ret;
+     }  
Hi Mauro,

With this patch, the ISC is broken on latest media tree. It looks like
pm_runtime_resume_and_get for the ISC_ISPCK clock returns -ENOACCESS and
thus, the probe of the driver fails:

atmel-sama5d2-isc f0008000.isc: failed to enable ispck: -13
atmel-sama5d2-isc: probe of f0008000.isc failed with error -13
What's the current status of this issue? 

If the bug still happens, we need a fix for it.

We might revert this patch, but this would just be masking some other
hidden bug.

Regards,
Mauro


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Could you point out how I could fix this ? Maybe the isc_clk->dev is not
properly handled/initialized in some other part of the code ?  
Looking at RPM implementation:

         static int rpm_resume(struct device *dev, int rpmflags)
         {
...
         if (dev->power.runtime_error)
                 retval = -EINVAL;
         else if (dev->power.disable_depth == 1 && dev->power.is_suspended
             && dev->power.runtime_status == RPM_ACTIVE)
                 retval = 1;
         else if (dev->power.disable_depth > 0)
                 retval = -EACCES;
...

It sounds that RPM is disabled for this clock. Did you call
pm_runtime_enable() before calling isc_clk_prepare()?

Thanks,
Mauro
  
I tried to call pm_runtime_enable for the clk at clk_init time, but 
doing that makes the runtime for the ISC fail like this:

atmel-sama5d2-isc f0008000.isc: Unbalanced pm_runtime_enable!


Thanks,
Mauro
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