[Intel-gfx] [PATCH] drm/i915: Enable PSR by default.

[Rodrigo Vivi]

With a reliable frontbuffer tracking and all instability corner cases
solved let's re-enabled PSR by default on all supported platforms.

In case a new issue is found and PSR is the main suspect, please check
if i915.enable_psr=0 really makes your problem go away. If this is the case
PSR is the culprit so after that please check if i915.enable_psr=2
solves your issue and please let us know. There are many panels out there
and not all implementations apparently work as we would expect.

In case you needed to force it on standby or disabled, please
report PCI device ID, subsystem vendor and subsystem device ID
to intel-gfx at lists.freedesktop.org, if your machine needs it.
It will then be included in an upcoming module version.

Also, if the standby mode doesn't help a bugzilla entry is desirable
containing:
- dmesg (drm.debug=0xe)
- Platform information. Vendor, model, id, pci id.
- Graphical environment: Gnome, KDE, openbox, etc...
- Details how to reproduce.
- Also good if you could run PSR test cases of Intel-gpu-tools

There are Intel-gpu-tools test cases that can be helpful to
determine if PSR is working as expected:
kms_psr_sink_crc and kms_psr_frontbuffer_tracking.

v2: Rebased on top of psr paramenter change.

v3: Rebase and improve commit message.

Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
---
 drivers/gpu/drm/i915/i915_params.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_params.c b/drivers/gpu/drm/i915/i915_params.c
index 6dd39f0..edec23c 100644
--- a/drivers/gpu/drm/i915/i915_params.c
+++ b/drivers/gpu/drm/i915/i915_params.c
@@ -37,7 +37,7 @@ struct i915_params i915 __read_mostly = {
 	.enable_execlists = -1,
 	.enable_hangcheck = true,
 	.enable_ppgtt = -1,
-	.enable_psr = 0,
+	.enable_psr = 1,
 	.preliminary_hw_support = IS_ENABLED(CONFIG_DRM_I915_PRELIMINARY_HW_SUPPORT),
 	.disable_power_well = -1,
 	.enable_ips = 1,
@@ -127,7 +127,7 @@ MODULE_PARM_DESC(enable_execlists,
 
 module_param_named_unsafe(enable_psr, i915.enable_psr, int, 0600);
 MODULE_PARM_DESC(enable_psr, "Enable PSR "
-		 "(0=disabled [default], 1=link-off maximum power-savings, 2=link-standby mode)"
+		 "(0=disabled, 1=link-off maximum power-savings [default], 2=link-standby mode)"
 		 "In case you needed to force it on standby or disabled, please "
 		 "report PCI device ID, subsystem vendor and subsystem device ID "
 		 "to intel-gfx at lists.freedesktop.org, if your machine needs it. "
-- 
2.4.3