Re: [PATCH v2 3/3] drm/i915: Add boot paramter to control rps boost at boot time.

["S, Deepak" <deepak.s@intel.com>]

On 3/13/2014 11:46 PM, Ville Syrjälä wrote:
> On Thu, Mar 13, 2014 at 09:30:18PM +0530, deepak.s@linux.intel.com wrote:
>> From: Deepak S <deepak.s@intel.com>
>>
>> We are adding a module paramter to control rps boost. By default, we
>> enable the boost for better performace. Based on the need (perf/power)
>> we can either enable/disable.
>>
>> v2: Addressed rps default comment (Jani)
>>
>> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_drv.h    |  1 +
>>   drivers/gpu/drm/i915/i915_gem.c    | 16 +++++++++++++++-
>>   drivers/gpu/drm/i915/i915_params.c |  5 +++++
>>   3 files changed, 21 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
>> index 607042b..7808319 100644
>> --- a/drivers/gpu/drm/i915/i915_drv.h
>> +++ b/drivers/gpu/drm/i915/i915_drv.h
>> @@ -2106,6 +2106,7 @@ struct i915_params {
>>   	int panel_use_ssc;
>>   	int vbt_sdvo_panel_type;
>>   	int enable_rc6;
>> +	int enable_rps_boost;
>
> Should be bool like Jani said. And then it should be thrown somewhere
> somewhere at the end of the structure next to the other bools.

I will address this.
>>   	int enable_fbc;
>>   	int enable_ppgtt;
>>   	int enable_psr;
>> diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
>> index 92b0b41..23a4700 100644
>> --- a/drivers/gpu/drm/i915/i915_gem.c
>> +++ b/drivers/gpu/drm/i915/i915_gem.c
>> @@ -1002,6 +1002,17 @@ static bool can_wait_boost(struct drm_i915_file_private *file_priv)
>>   	return !atomic_xchg(&file_priv->rps_wait_boost, true);
>>   }
>>
>> +static int  intel_enable_rps_boost(struct drm_device *dev)
>> +{
>> +	/* No RPS Boost before Ironlake */
>
> This comment is still wrong. I'd just drop it, everyone should know what
> the gen check below means.
Ok
>> +	if (INTEL_INFO(dev)->gen < 6)
>> +		return 0;
>> +
>> +	/* Respect the kernel parameter if it is set */
>
> This comment too seems rather obvious. I'd drop it as well.
Ok
>> +	return i915.enable_rps_boost;
>> +
>> +}
>
> This function is still just a wrapper for i915.enable_rps_boost since
> __wait_seqno() already does the gen check. You could just check
> i915.enable_rps_boost directly in __wait_seqno(). The other option is
> to just drop the gen check from __wait_seqno() and just let this
> function take care of it. Hmm. Yeah that might be the nicest choice in
> fact.
Agreed. Does not make sense to have multiple platform check's.
>> +
>>   /**
>>    * __wait_seqno - wait until execution of seqno has finished
>>    * @ring: the ring expected to report seqno
>> @@ -1042,8 +1053,11 @@ static int __wait_seqno(struct intel_ring_buffer *ring, u32 seqno,
>>
>>   	timeout_expire = timeout ? jiffies + timespec_to_jiffies_timeout(timeout) : 0;
>>
>> -	if (INTEL_INFO(dev)->gen >= 6 && can_wait_boost(file_priv)) {
>> +	if (INTEL_INFO(dev)->gen >= 6 && can_wait_boost(file_priv) &&
>> +			intel_enable_rps_boost(ring->dev)) {
>
> Indentation is quite wrong. There's also trailing whitespace around
> these parts. Please run patches through checkpatch.pl before submitting.
>
>> +		
>>   		gen6_rps_boost(dev_priv);
>> +
>>   		if (file_priv)
>>   			mod_delayed_work(dev_priv->wq,
>>   					 &file_priv->mm.idle_work,
>> diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
>> index a66ffb6..2d207e3 100644
>> --- a/drivers/gpu/drm/i915/i915_params.c
>> +++ b/drivers/gpu/drm/i915/i915_params.c
>> @@ -34,6 +34,7 @@ struct i915_params i915 __read_mostly = {
>>   	.panel_use_ssc = -1,
>>   	.vbt_sdvo_panel_type = -1,
>>   	.enable_rc6 = -1,
>> +	.enable_rps_boost = 1,
>
> true
>
>>   	.enable_fbc = -1,
>>   	.enable_hangcheck = true,
>>   	.enable_ppgtt = -1,
>> @@ -78,6 +79,10 @@ MODULE_PARM_DESC(enable_rc6,
>>   	"For example, 3 would enable rc6 and deep rc6, and 7 would enable everything. "
>>   	"default: -1 (use per-chip default)");
>>
>> +module_param_named(enable_rps_boost, i915.enable_rps_boost, int, 0600);
>
> bool
>
>> +MODULE_PARM_DESC(enable_rps_boost,
>> +		"Enable/Disable boost RPS frequency (default: enabled (1))");
>
> default: true
>
>> +
>>   module_param_named(enable_fbc, i915.enable_fbc, int, 0600);
>>   MODULE_PARM_DESC(enable_fbc,
>>   	"Enable frame buffer compression for power savings "
>> --
>> 1.8.4.2
>>
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>