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From: Henrik Rydberg <rydberg@bitmath.org>
To: Brad Campbell <brad@fnarfbargle.com>, linux-hwmon@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	hns@goldelico.com, Andreas Kemnade <andreas@kemnade.info>,
	Jean Delvare <jdelvare@suse.com>,
	Guenter Roeck <linux@roeck-us.net>
Subject: Re: [PATCH v5 1/1] applesmc: Re-work SMC comms
Date: Wed, 11 Nov 2020 21:05:59 +0100	[thread overview]
Message-ID: <29b03865-f00a-f121-b7a5-c4b9179a27cb@bitmath.org> (raw)
In-Reply-To: <8c525b3b-b4a6-8ee4-8128-a20e0ad408e4@fnarfbargle.com>

On 2020-11-11 14:06, Brad Campbell wrote:
> Commit fff2d0f701e6 ("hwmon: (applesmc) avoid overlong udelay()")
> introduced an issue whereby communication with the SMC became
> unreliable with write errors like :
> 
> [  120.378614] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> [  120.378621] applesmc: LKSB: write data fail
> [  120.512782] applesmc: send_byte(0x00, 0x0300) fail: 0x40
> [  120.512787] applesmc: LKSB: write data fail
> 
> The original code appeared to be timing sensitive and was not reliable
> with the timing changes in the aforementioned commit.
> 
> This patch re-factors the SMC communication to remove the timing
> dependencies and restore function with the changes previously
> committed. Logic changes based on inspection of the Apple SMC kext.
> 
> Tested on : MacbookAir6,2 MacBookPro11,1 iMac12,2, MacBookAir1,1,
> MacBookAir3,1
> 
> Fixes: fff2d0f701e6 ("hwmon: (applesmc) avoid overlong udelay()")
> Reported-by: Andreas Kemnade <andreas@kemnade.info>
> Tested-by: Andreas Kemnade <andreas@kemnade.info> # MacBookAir6,2
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Brad Campbell <brad@fnarfbargle.com>
> Signed-off-by: Henrik Rydberg <rydberg@bitmath.org>
> 
> ---
> Changelog :
> v1 : Initial attempt
> v2 : Address logic and coding style
> v3 : Removed some debug hangover. Added tested-by. Modifications for MacBookAir1,1
> v4 : Re-factored logic based on Apple driver. Simplified wait_status loop
> v5 : Re-wrote status loop. Simplified busy check in send_byte(). Fixed formatting

Hi Brad,

This version is still working fine on the MBA1,1, at 50 reads per second.

Thanks,
Henrik

  reply	other threads:[~2020-11-11 20:05 UTC|newest]

Thread overview: 59+ 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
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 [this message]
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
2020-11-09  9:27                             ` kernel test robot
2020-11-05  9:48                       ` [REGRESSION] hwmon: (applesmc) avoid overlong udelay() Arnd Bergmann

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