On 9/6/21 11:13 AM, Eugen Hristev - M18282 wrote:

On 9/6/21 11:03 AM, Mauro Carvalho Chehab wrote:

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Hi Eugen,

Em Thu, 10 Jun 2021 12:00:42 +0000
[off-list ref] escreveu:

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On 6/10/21 12:38 PM, Mauro Carvalho Chehab wrote:

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Em Thu, 10 Jun 2021 09:04:07 +0000
[off-list ref] escreveu:

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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?

Hi Mauro,

Currently, as far as I know, the ISC is broken in 5.14 and current Linux
master. I plan to investigate this issue this week (or the next...),
together with some other things. I want to tryout the PM part of the
driver to see where is the problem.
When I come up with a fix or patch, I will send it on the mailing list.
If you have any ideas that I can try meanwhile, feel free to contact me
to send a patch that I can test.

Hi Mauro,

Regarding this issue, I sent a patch on the ML that should solve it.

https://patchwork.linuxtv.org/project/linux-media/patch/20210913102254.108638-1-eugen.hristev@microchip.com/

Eugen

Eugen

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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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