[Intel-gfx] [PATCH v4 11/26] drm/i915/slpc: Update sysfs/debugfs interfaces for frequency parameters

[Chris Wilson]

On Thu, Sep 15, 2016 at 04:11:45PM +0530, Kamble, Sagar A wrote:
> 
> 
> On 9/9/2016 10:43 PM, Chris Wilson wrote:
> >On Fri, Sep 09, 2016 at 06:21:30PM +0530, Sagar Arun Kamble wrote:
> >>From: Tom O'Rourke <Tom.O'Rourke at intel.com>
> >>
> >>When SLPC is controlling requested frequency, the rps.cur_freq
> >>value is not used to make the frequency request.
> >>
> >>Requested frequency from register RPNSWREQ has the value
> >>most recently requested by SLPC firmware. Adding new sysfs
> >>interface gt_req_freq_mhz to know this value.
> >>SLPC requested value needs to be made available to i915 without
> >>reading RPNSWREQ.
> >>
> >>v1: Replace HAS_SLPC with intel_slpc_active (Paulo)
> >>     Avoid magic numbers (Nick)
> >>     Use a function for repeated code (Jon)
> >>
> >>v2: Add "SLPC Active" to i915_frequency_info output and
> >>     don't update cur_freq as it is driver internal request. (Chris)
> >>
> >>v3: Removing sysfs interface gt_req_freq_mhz out of this patch
> >>     for proper division of functionality. (Sagar)
> >>
> >>v4: idle_freq, boost_freq are also not used with SLPC.
> >>
> >>Signed-off-by: Tom O'Rourke <Tom.O'Rourke at intel.com>
> >>Signed-off-by: Sagar Arun Kamble <sagar.a.kamble at intel.com>
> >>---
> >>  drivers/gpu/drm/i915/i915_debugfs.c | 24 ++++++++++++++++++------
> >>  drivers/gpu/drm/i915/i915_sysfs.c   |  3 +++
> >>  2 files changed, 21 insertions(+), 6 deletions(-)
> >>
> >>diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> >>index 02b627e..71bce32 100644
> >>--- a/drivers/gpu/drm/i915/i915_debugfs.c
> >>+++ b/drivers/gpu/drm/i915/i915_debugfs.c
> >>@@ -1083,6 +1083,9 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
> >>  	intel_runtime_pm_get(dev_priv);
> >>+	if (intel_slpc_active(dev_priv))
> >>+		seq_puts(m, "SLPC Active\n");
> >>+
> >>  	if (IS_GEN5(dev_priv)) {
> >>  		u16 rgvswctl = I915_READ16(MEMSWCTL);
> >>  		u16 rgvstat = I915_READ16(MEMSTAT_ILK);
> >>@@ -1250,15 +1253,21 @@ static int i915_frequency_info(struct seq_file *m, void *unused)
> >>  		seq_printf(m, "Max overclocked frequency: %dMHz\n",
> >>  			   intel_gpu_freq(dev_priv, dev_priv->rps.max_freq));
> >>-		seq_printf(m, "Current freq: %d MHz\n",
> >>-			   intel_gpu_freq(dev_priv, dev_priv->rps.cur_freq));
> >>+		if (!intel_slpc_active(dev_priv)) {
> >Just keep printing them, we have the banner upfront, and being able to
> >track and compare internal values vs hw state is still important. (And
> >the ordering was fairly intentional.)
> cur_freq, idle_freq, boost_freq will not be applicable with SLPC.
> With SLPC we should rely on value from RPNSWREQ for cur_freq.

Hence the banner. We still want to be able to inspect our internal
values to see if anything is going wrong, whether SLPC is enabled or
not. E.g. if SLPC is and yet the bookkeeping is changing, something is
wrong.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre