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* Re: Re: [PATCH] PM / devfreq: Use freq_table for available_frequencies
@ 2014-04-15  1:36 ` 함명주
  0 siblings, 0 replies; 12+ messages in thread
From: 함명주 @ 2014-04-15  1:36 UTC (permalink / raw)
  To: Saravana Kannan
  Cc: 박경민,
	linux-pm, linux-kernel, linux-arm-msm, linux-arm-kernel

> MyungJoo/Kyungmin,
> 
> Bump. Can we accept this patch please?
> 
> -Saravana

Nack.

Please note that freq_table is also an optional value, which may
be null.

Besides, please be aware that your code is under rcu_read_lock().


Cheers,
MyungJoo.

ps. I'll send a related patch (avoid accessing null but not-an-error
pointer at other sysfs nodes). Thank you for letting me catch such bugs anyway.

> 
> 
> On 04/10/2014 07:54 PM, Saravana Kannan wrote:
> > Some devices use freq_table instead of OPP. For those devices, the
> > available_frequencies file shows up empty. Fix that by using freq_table to
> > generate the available_frequencies data when OPP is not present.
> >
> > Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
> > ---
> >   drivers/devfreq/devfreq.c | 15 +++++++++++----
> >   1 file changed, 11 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
> > index 2042ec3..a715d15 100644
> > --- a/drivers/devfreq/devfreq.c
> > +++ b/drivers/devfreq/devfreq.c
> > @@ -912,19 +912,26 @@ static ssize_t available_frequencies_show(struct device *d,
> >   	struct devfreq *df = to_devfreq(d);
> >   	struct device *dev = df->dev.parent;
> >   	struct dev_pm_opp *opp;
> > +	unsigned int i = 0, max_state = df->profile->max_state;
> > +	bool use_opp;
> >   	ssize_t count = 0;
> >   	unsigned long freq = 0;
> >
> >   	rcu_read_lock();
> > +	use_opp = dev_pm_opp_get_opp_count(dev) > 0;
> >   	do {
> > -		opp = dev_pm_opp_find_freq_ceil(dev, &freq);
> > -		if (IS_ERR(opp))
> > -			break;
> > +		if (use_opp) {
> > +			opp = dev_pm_opp_find_freq_ceil(dev, &freq);
> > +			if (IS_ERR(opp))
> > +				break;
> > +		} else {
> > +			freq = df->profile->freq_table[i++];
> > +		}
> >
> >   		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
> >   				   "%lu ", freq);
> >   		freq++;
> > -	} while (1);
> > +	} while (use_opp || (!use_opp && i < max_state));
> >   	rcu_read_unlock();
> >
> >   	/* Truncate the trailing space */
> >
> 
> 
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation
> 
> 
> 
>        
>   
>          
> 

^ permalink raw reply	[flat|nested] 12+ messages in thread
* Re: Re: [PATCH] PM / devfreq: Use freq_table for available_frequencies
@ 2014-04-15  6:30 함명주
  2014-04-15 18:41   ` Saravana Kannan
  0 siblings, 1 reply; 12+ messages in thread
From: 함명주 @ 2014-04-15  6:30 UTC (permalink / raw)
  To: Saravana Kannan
  Cc: 박경민,
	linux-pm, linux-kernel, linux-arm-msm, linux-arm-kernel

> On 04/14/2014 06:36 PM, 함명주 wrote:
> >> MyungJoo/Kyungmin,
> >>
> >> Bump. Can we accept this patch please?
> >>
> >> -Saravana
> > 
> > Nack.
> > 
> > Please note that freq_table is also an optional value, which may
> > be null.
> 
> Ah, I saw that the max_freq would be zero if freq_table was NULL and I
> assumed that it can't be NULL. But I see that the max_freq limit is not
> applied if it's zero. Thanks for catching it.
> 
> > Besides, please be aware that your code is under rcu_read_lock().
> 
> Valid point. I was just trying to keep the diff simple. No one's really
> going to be catting this file often when performance matters.
> 
> > 
> > 
> > Cheers,
> > MyungJoo.
> > 
> > ps. I'll send a related patch (avoid accessing null but not-an-error
> > pointer at other sysfs nodes). Thank you for letting me catch such bugs anyway.
> 
> I can go ahead and do this myself if you don't mind.

No, we don't need it. It was a false alarm.
Reading again, I've found that we've already made other sysfs nodes
check if either freq_table is null or its size is 0.

So, we only need to look at this available_frequencies node now.

I'll add some notes on the ABI doc for available_frequencies soon.

Cheers,
MyungJoo.

> 
> -Saravana
> 
> -- 
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> hosted by The Linux Foundation
> 
> 
> 
>        
>   
>          
> 

^ permalink raw reply	[flat|nested] 12+ messages in thread
* [PATCH] PM / devfreq: Use freq_table for available_frequencies
@ 2014-04-11  2:54 ` Saravana Kannan
  0 siblings, 0 replies; 12+ messages in thread
From: Saravana Kannan @ 2014-04-11  2:54 UTC (permalink / raw)
  To: MyungJoo Ham, Kyungmin Park
  Cc: linux-pm, linux-kernel, linux-arm-msm, linux-arm-kernel, Saravana Kannan

Some devices use freq_table instead of OPP. For those devices, the
available_frequencies file shows up empty. Fix that by using freq_table to
generate the available_frequencies data when OPP is not present.

Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
---
 drivers/devfreq/devfreq.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index 2042ec3..a715d15 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -912,19 +912,26 @@ static ssize_t available_frequencies_show(struct device *d,
 	struct devfreq *df = to_devfreq(d);
 	struct device *dev = df->dev.parent;
 	struct dev_pm_opp *opp;
+	unsigned int i = 0, max_state = df->profile->max_state;
+	bool use_opp;
 	ssize_t count = 0;
 	unsigned long freq = 0;
 
 	rcu_read_lock();
+	use_opp = dev_pm_opp_get_opp_count(dev) > 0;
 	do {
-		opp = dev_pm_opp_find_freq_ceil(dev, &freq);
-		if (IS_ERR(opp))
-			break;
+		if (use_opp) {
+			opp = dev_pm_opp_find_freq_ceil(dev, &freq);
+			if (IS_ERR(opp))
+				break;
+		} else {
+			freq = df->profile->freq_table[i++];
+		}
 
 		count += scnprintf(&buf[count], (PAGE_SIZE - count - 2),
 				   "%lu ", freq);
 		freq++;
-	} while (1);
+	} while (use_opp || (!use_opp && i < max_state));
 	rcu_read_unlock();
 
 	/* Truncate the trailing space */
-- 
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
hosted by The Linux Foundation

^ permalink raw reply related	[flat|nested] 12+ messages in thread

end of thread, other threads:[~2014-04-17  0:12 UTC | newest]

Thread overview: 12+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-04-15  1:36 Re: [PATCH] PM / devfreq: Use freq_table for available_frequencies 함명주
2014-04-15  1:36 ` 함명주
2014-04-15  5:16 ` Saravana Kannan
2014-04-15  5:16   ` Saravana Kannan
  -- strict thread matches above, loose matches on Subject: below --
2014-04-15  6:30 함명주
2014-04-15 18:41 ` Saravana Kannan
2014-04-15 18:41   ` Saravana Kannan
2014-04-17  0:12   ` Saravana Kannan
2014-04-17  0:12     ` Saravana Kannan
2014-04-11  2:54 Saravana Kannan
2014-04-11  2:54 ` Saravana Kannan
2014-04-14 20:51 ` Saravana Kannan
2014-04-14 20:51   ` Saravana Kannan

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