[PATCH] PM / devfreq: Use freq_table for available_frequencies

[PATCH] PM / devfreq: Use freq_table for available_frequencies

[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 */
-- 
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[PATCH] PM / devfreq: Use freq_table for available_frequencies

[Saravana Kannan]

MyungJoo/Kyungmin,

Bump. Can we accept this patch please?

-Saravana


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 */
>


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[PATCH] PM / devfreq: Use freq_table for available_frequencies

[Saravana Kannan]

On 04/14/2014 06:36 PM, ??? 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.

-Saravana

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[PATCH] PM / devfreq: Use freq_table for available_frequencies

[Saravana Kannan]

On 04/14/2014 11:30 PM, ??? wrote:
>> On 04/14/2014 06:36 PM, ??? 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.
> 

Ah, I misunderstood your previous email. I thought you Nack-ed my patch
and decided to send your own patch to replace mine. Ok, I'll fix up mine
and send it out.

-Saravana


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[PATCH] PM / devfreq: Use freq_table for available_frequencies

[Saravana Kannan]

On 04/15/2014 11:41 AM, Saravana Kannan wrote:
> Ah, I misunderstood your previous email. I thought you Nack-ed my patch
> and decided to send your own patch to replace mine. Ok, I'll fix up mine
> and send it out.

MyungJoo/Kyungmin,

I sent out an updated patch. Can you please take a look?

Thanks,
Saravana


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