[Intel-gfx] [PATCH v2] drm/i915/guc/slpc: Apply min softlimit correctly

[Vinay Belgaumkar]

The scenario being fixed here is depicted in the following sequence-

modprobe i915
echo 1 > /sys/class/drm/card0/gt/gt0/slpc_ignore_eff_freq
echo 300 > /sys/class/drm/card0/gt_min_freq_mhz (RPn)
cat /sys/class/drm/card0/gt_cur_freq_mhz --> cur == RPn as expected
echo 1 > /sys/kernel/debug/dri/0/gt0/reset --> reset
cat /sys/class/drm/card0/gt_min_freq_mhz --> cached freq is RPn
cat /sys/class/drm/card0/gt_cur_freq_mhz --> it's not RPn, but RPe!!

When SLPC reinitializes, it sets SLPC min freq to efficient frequency.
Even if we disable efficient freq post that, we should restore the cached
min freq (via H2G) for it to take effect.

v2: Clarify commit message (Ashutosh)

Fixes: 95ccf312a1e4 ("drm/i915/guc/slpc: Allow SLPC to use efficient frequency")
Reviewed-by: Ashutosh Dixit <ashutosh.dixit at intel.com>
Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
---
 drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
index 01b75529311c..ee9f83af7cf6 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_slpc.c
@@ -606,7 +606,7 @@ static int slpc_set_softlimits(struct intel_guc_slpc *slpc)
 		if (unlikely(ret))
 			return ret;
 		slpc_to_gt(slpc)->defaults.min_freq = slpc->min_freq_softlimit;
-	} else if (slpc->min_freq_softlimit != slpc->min_freq) {
+	} else {
 		return intel_guc_slpc_set_min_freq(slpc,
 						   slpc->min_freq_softlimit);
 	}
-- 
2.38.1