Dear Christian,
Am 22.06.20 um 19:41 schrieb Christian König:
Am 22.06.20 um 19:25 schrieb Paul Menzel:
Am 22.06.20 um 15:39 schrieb Christian König:
Am 19.06.20 um 20:50 schrieb Paul Menzel:
Currently, besides there is no explicit message, that DPM is disabled.
The user would need to know, that the missing success line indicates
that.
[drm] amdgpu: dpm initialized
So, add an explicit message, and make it log level warning, as
disabling
dpm is not the default, and device performance will most likely suffer.
Resolves:
https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgitlab.freedesktop.org%2Fdrm%2Famd%2F-%2Fissues%2F1173&data=02%7C01%7Cchristian.koenig%40amd.com%7C72d0b71d439e46d6253f08d816d150c6%7C3dd8961fe4884e608e11a82d994e183d%7C0%7C0%7C637284435558396492&sdata=5EXY1o1zwXJRzN9fqpUg%2BQNJGB3zAlWKnGWsdFXRcjA%3D&reserved=0
That URL is not mine. ;-)
Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
---
v2: Use new print helpers, and inform user about effects.
drivers/gpu/drm/amd/amdgpu/kv_dpm.c | 4 +++-
drivers/gpu/drm/amd/amdgpu/si_dpm.c | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/kv_dpm.c
b/drivers/gpu/drm/amd/amdgpu/kv_dpm.c
index f054ded902f2..c601587c6d59 100644
--- a/drivers/gpu/drm/amd/amdgpu/kv_dpm.c
+++ b/drivers/gpu/drm/amd/amdgpu/kv_dpm.c
@@ -3014,8 +3014,10 @@ static int kv_dpm_sw_init(void *handle)
adev->pm.current_mclk = adev->clock.default_mclk;
adev->pm.int_thermal_type = THERMAL_TYPE_NONE;
- if (amdgpu_dpm == 0)
+ if (amdgpu_dpm == 0) {
+ drm_warn(adev, "amdgpu: dpm disabled per parameter. Your
graphics device will run with lower clocks impacting graphics
performance.\n");
I'm not very keen about this. When an user specifies that DPM
shouldn't be used the driver doesn't need to inform the user about
this once more.
In other words shooting in your own foot is supposed to hurt.
Maybe. The other point of view is, how does having the clarity in the
logs hurt?
Well, you are spamming the logs with a warning about an intentional
behavior.
For example, if the user added the parameter intentionally, maybe they
made a typo, and it’s actually not applied. Or there is a bug in the
parameter handling. Having explicit log messages is good in my opinion.
Secondly, the parameter could have been left there unintentionally.
Having the message in the logs, makes the user aware of that.
And exactly for this reason the kernel command line is printed as the
second line of the logs.
No, I disagree. Having the parameters listed, and knowing the actual
effects are two totally different things. It’s user interface design 101
to give clear feedback. I think, you are looking through the glasses of
a developer, and not of a non-developer.
Duplicating this in each driver is not only overkill, but also very
error prone.
What drivers do you mean, and what is error prone?
Sorry, but this is absolutely don't think that this is a good idea.
Despite other subsystems actually “spamming” the logs for parameters
given on the command line, here is my motivation.
Unfortunately, there is a serious issue with first(?) generation Ryzen
CPUs, and maybe even external AMD graphics cards [1]. In comment 29 it
is suggested to use `amdgpu.dpm=0` [1], and further it’s said, it’s
disabling power management. Reading the comments further [2], the user
gets the impression turning off power management will cause the device
to be operated at the highest performance [3].
Trying this option, I was surprised of the degraded performance, and
only in #radeon@xxxxxxxxxxxxxxxx my question was answered, saying that
it’s actually depending on the system firmware how clocks are set up,
and it’s common to use the *lowest* clocks. So the warning message,
would have helped me a lot.
So, especially with these option used by “normal” users, having clear
feedback on specified option, especially those decreasing performance,
is very important.
Kind regards,
Paul
return 0;
+ }
INIT_WORK(&adev->pm.dpm.thermal.work,
amdgpu_dpm_thermal_work_handler);
mutex_lock(&adev->pm.mutex);
diff --git a/drivers/gpu/drm/amd/amdgpu/si_dpm.c
b/drivers/gpu/drm/amd/amdgpu/si_dpm.c
index f7edc1d50df4..1f35d5a36300 100644
--- a/drivers/gpu/drm/amd/amdgpu/si_dpm.c
+++ b/drivers/gpu/drm/amd/amdgpu/si_dpm.c
@@ -7687,8 +7687,10 @@ static int si_dpm_sw_init(void *handle)
adev->pm.current_mclk = adev->clock.default_mclk;
adev->pm.int_thermal_type = THERMAL_TYPE_NONE;
- if (amdgpu_dpm == 0)
+ if (amdgpu_dpm == 0) {
+ drm_warn(adev, "amdgpu: dpm disabled per parameter. Your
graphics device will run with lower clocks impacting graphics
performance.\n");
return 0;
+ }
ret = si_dpm_init_microcode(adev);
if (ret)
[1]: https://bugzilla.kernel.org/show_bug.cgi?id=206903#c29
[2]: https://bugzilla.kernel.org/show_bug.cgi?id=206903#c33
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