From: Henrik Rydberg <rydberg@bitmath.org>
To: Brad Campbell <brad@fnarfbargle.com>,
Andreas Kemnade <andreas@kemnade.info>
Cc: Arnd Bergmann <arnd@arndb.de>,
linux-hwmon@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
hns@goldelico.com, Guenter Roeck <linux@roeck-us.net>,
Jean Delvare <jdelvare@suse.com>
Subject: Re: [PATCH v3] applesmc: Re-work SMC comms
Date: Sun, 8 Nov 2020 13:04:32 +0100 [thread overview]
Message-ID: <af08ee3b-313d-700c-7e70-c57d20d3be5d@bitmath.org> (raw)
In-Reply-To: <bdabe861-8717-8948-80a0-ca2173c2e22a@fnarfbargle.com>
On 2020-11-08 12:57, Brad Campbell wrote:
> On 8/11/20 9:14 pm, Henrik Rydberg wrote:
>> On Sun, Nov 08, 2020 at 09:35:28AM +0100, Henrik Rydberg wrote:
>>> Hi Brad,
>>>
>>> On 2020-11-08 02:00, Brad Campbell wrote:
>>>> G'day Henrik,
>>>>
>>>> I noticed you'd also loosened up the requirement for SMC_STATUS_BUSY in read_smc(). I assume
>>>> that causes problems on the early Macbook. This is revised on the one sent earlier.
>>>> If you could test this on your Air1,1 it'd be appreciated.
>>>
>>> No, I managed to screw up the patch; you can see that I carefully added the
>>> same treatment for the read argument, being unsure if the BUSY state would
>>> remain during the AVAILABLE data phase. I can check that again, but
>>> unfortunately the patch in this email shows the same problem.
>>>
>>> I think it may be worthwhile to rethink the behavior of wait_status() here.
>>> If one machine shows no change after a certain status bit change, then
>>> perhaps the others share that behavior, and we are waiting in vain. Just
>>> imagine how many years of cpu that is, combined. ;-)
>>
>> Here is a modification along that line.
>>
>> Compared to your latest version, this one has wait_status() return the
>> actual status on success. Instead of waiting for BUSY, it waits for
>> the other status bits, and checks BUSY afterwards. So as not to wait
>> unneccesarily, the udelay() is placed together with the single
>> outb(). The return value of send_byte_data() is augmented with
>> -EAGAIN, which is then used in send_command() to create the resend
>> loop.
>>
>> I reach 41 reads per second on the MBA1,1 with this version, which is
>> getting close to the performance prior to the problems.
>
> G'day Henrik,
>
> I like this one. It's slower on my laptop (40 rps vs 50 on the MacbookPro11,1) and the same 17 rps on the iMac 12,2 but it's as reliable
> and if it works for both of yours then I think it's a winner. I can't really diagnose the iMac properly as I'm 2,800KM away and have
> nobody to reboot it if I kill it. 5.7.2 gives 20 rps, so 17 is ok for me.
>
> Andreas, could I ask you to test this one?
>
> Odd my original version worked on your Air3,1 and the other 3 machines without retry.
> I wonder how many commands require retries, how many retires are actually required, and what we are going wrong on the Air1,1 that requires
> one or more retries.
>
> I just feels like a brute force approach because there's something we're missing.
I would think you are right. There should be a way to follow the status
changes in realtime, so one can determine handshake and processing from
that information. At least, with this change, we are making the blunt
instrument a little smaller.
Cheers,
Henrik
next prev parent reply other threads:[~2020-11-08 12:04 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 8:54 [REGRESSION] hwmon: (applesmc) avoid overlong udelay() Andreas Kemnade
2020-09-30 16:44 ` Guenter Roeck
2020-09-30 20:00 ` Arnd Bergmann
2020-10-01 22:22 ` Andreas Kemnade
2020-10-02 4:07 ` Guenter Roeck
2020-10-06 7:02 ` Andreas Kemnade
2020-11-02 23:56 ` Brad Campbell
2020-11-03 5:56 ` Brad Campbell
2020-11-04 13:20 ` Andreas Kemnade
2020-11-05 2:18 ` Brad Campbell
2020-11-05 4:22 ` Brad Campbell
2020-11-05 4:43 ` Guenter Roeck
2020-11-05 5:05 ` Brad Campbell
2020-11-05 5:26 ` Guenter Roeck
2020-11-05 5:47 ` [PATCH] applesmc: Re-work SMC comms v1 Brad Campbell
2020-11-05 7:26 ` [PATCH] applesmc: Re-work SMC comms v2 Brad Campbell
2020-11-05 7:56 ` Henrik Rydberg
2020-11-05 8:15 ` Andreas Kemnade
2020-11-05 8:30 ` Brad Campbell
2020-11-05 10:31 ` Henrik Rydberg
2020-11-06 16:26 ` Henrik Rydberg
2020-11-06 20:02 ` Henrik Rydberg
2020-11-07 18:31 ` Henrik Rydberg
2020-11-08 0:09 ` Brad Campbell
2020-11-08 8:22 ` Henrik Rydberg
2020-11-08 1:00 ` [PATCH v3] applesmc: Re-work SMC comms Brad Campbell
2020-11-08 8:35 ` Henrik Rydberg
2020-11-08 10:14 ` Henrik Rydberg
2020-11-08 11:57 ` Brad Campbell
2020-11-08 12:04 ` Henrik Rydberg [this message]
2020-11-09 13:06 ` Brad Campbell
2020-11-09 17:08 ` Henrik Rydberg
2020-11-09 22:52 ` Brad Campbell
2020-11-08 16:06 ` Guenter Roeck
2020-11-09 0:25 ` Brad Campbell
2020-11-10 2:04 ` Brad Campbell
2020-11-10 4:55 ` Guenter Roeck
2020-11-10 5:40 ` Brad Campbell
2020-11-10 16:02 ` Guenter Roeck
2020-11-09 8:44 ` Andreas Kemnade
2020-11-09 9:51 ` Brad Campbell
2020-11-11 3:37 ` [PATCH v4 0/1] " Brad Campbell
2020-11-11 4:55 ` [PATCH v1] applesmc: Cleanups on top of re-work comms Brad Campbell
2020-11-11 3:38 ` [PATCH v4 1/1] applesmc: Re-work SMC comms Brad Campbell
2020-11-11 5:56 ` Guenter Roeck
2020-11-11 7:05 ` Brad Campbell
2020-11-11 13:06 ` [PATCH v5 " Brad Campbell
2020-11-11 20:05 ` Henrik Rydberg
2020-11-11 23:28 ` Brad Campbell
2020-11-12 3:08 ` [PATCH v6 " Brad Campbell
2020-11-12 17:20 ` Guenter Roeck
2020-11-06 23:11 ` [PATCH] applesmc: Re-work SMC comms v2 Brad Campbell
2020-11-05 8:12 ` Andreas Kemnade
2020-11-05 16:12 ` Guenter Roeck
2020-11-06 0:02 ` Brad Campbell
2020-11-06 3:08 ` Guenter Roeck
2020-11-09 9:27 ` [PATCH] applesmc: Re-work SMC comms v1 kernel test robot
2020-11-05 9:48 ` [REGRESSION] hwmon: (applesmc) avoid overlong udelay() Arnd Bergmann
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