Re: [PATCH v2 2/3] hwmon: (asus_wmi_ec_sensors) Support B550 Asus WMI.
From: Guenter Roeck
Date: Sun Oct 10 2021 - 10:33:11 EST
On 10/10/21 6:46 AM, Eugene Shalygin wrote:
Hi Denis,
On Sun, 10 Oct 2021 at 12:39, Denis Pauk <pauk.denis@xxxxxxxxx> wrote:
Hi Eugene,
As for me, use WMI methods will be more reliable and cover more
motherboards.
Why do you believe they are more reliable? How does it cover more motherboards?
You said yourself below: "I know the naive reading from the ACPI EC registers
leads to problems (fans get stuck, etc.)".
Something in the WMI code is obviously broken and, ultimately, will need
to get fixed. I don't know if that something is on the ASUS side or on the
kernel side, or on the interface between the two. A single WMI call taking
1 second is way too long and strongly suggests that some timeout is involved.
Not using WMI because of that just seems wrong.
Guenter
Thanks,
Eugene
Best regards,
Denis.
On Thu, 7 Oct 2021 20:11:33 +0200
Eugene Shalygin <eugene.shalygin@xxxxxxxxx> wrote:
Denis and All,
regarding the asus-wmi-ec-sensors driver: it uses a WMI method to read
EC registers, and this method is slow (requires almost a full second
for a single call). Maybe I'm doing something wrong, but my impression
is that the WMI calls themselves are that slow. I will try to
reimplement this driver using direct EC operations and the global ACPI
lock with a hope to make it read sensors quicker. If that works out,
perhaps the nct6775 may go the same way, as it suffers too from the
slow WMI calls. I know next to nothing about the ACPI system and learn
from the beginning, so I'm not sure about the result. I know the naive
reading from the ACPI EC registers leads to problems (fans get stuck,
etc.), and if someone with knowledge can assure me that the idea with
the ACPI global lock (as far as I understand it is even implemented in
the ec kernel driver already) is correct, I would even request to stop
accepting the EC WMI sensors driver, as it is so slow (albeit dead
simple and small).
Best regards,
Eugen