gpu: nvgpu: gk20a: Fix up qos/sysfs limits

Userspace sysfs limits devfreq->{min|max}_freq and pmqos min/max limits
are treated as the same priority. In case these two ranges don't intersect
prefer the max_freq clamp over the min_freq clamp.

This is done in order to ensure any thermal throttling isn't bypassed by a
userspace sysfs write. MaxQ/MaxP configurations only care about the Fmax
limit and not necessarily Fmin, so preferring max_freq over min_freq is
consistent with what is required.

Bug 1933216

Change-Id: Ie8685306f10dee0f8d340c4b8e0eae533dbfc6ac
Signed-off-by: Sai Gurrappadi <sgurrappadi@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1535937
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
Reviewed-by: Aaron Huang <aaronh@nvidia.com>
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: svc-mobile-misra <svc-mobile-misra@nvidia.com>
Reviewed-by: Deepak Nibade <dnibade@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 2 insertions, 8 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/gk20a_scale.c b/drivers/gpu/nvgpu/gk20a/gk20a_scale.c
index 6f4f7dc9..3e6fead6 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a_scale.c
+++ b/drivers/gpu/nvgpu/gk20a/gk20a_scale.c
@@ -160,19 +160,13 @@ static int gk20a_scale_target(struct device *dev, unsigned long *freq,
          * To get cap (max) freq, we select MIN of max frequencies
          *
          * In case we have conflict (min_freq > max_freq) after above
-         * steps, we ensure that devfreq->min_freq wins over
-         * qos_max_freq
+         * steps, we ensure that max_freq wins over min_freq
          */
         min_freq = max_t(u32, devfreq->min_freq, profile->qos_min_freq);
         max_freq = min_t(u32, devfreq->max_freq, profile->qos_max_freq);
 
-        if (min_freq > max_freq) {
-                if (min_freq == devfreq->min_freq &&
-                    max_freq != devfreq->max_freq) {
-                        max_freq = min_t(u32, min_freq, devfreq->max_freq);
-                }
+        if (min_freq > max_freq)
                 min_freq = max_freq;
-        }
 
         /* Clip requested frequency */
         if (local_freq < min_freq)