From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1949289AbcBTBPh (ORCPT ); Fri, 19 Feb 2016 20:15:37 -0500 Received: from bh-25.webhostbox.net ([208.91.199.152]:46899 "EHLO bh-25.webhostbox.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993604AbcBTBPY (ORCPT ); Fri, 19 Feb 2016 20:15:24 -0500 Subject: Re: [PATCH] hwmon: (gpio-fan) Remove un-necessary speed_index lookup for thermal hook To: Nishanth Menon , Jean Delvare References: <1455926991-15189-1-git-send-email-nm@ti.com> Cc: Tony Lindgren , linux-kernel@vger.kernel.org, lm-sensors@lm-sensors.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Eduardo Valentin From: Guenter Roeck Message-ID: <56C7BE28.2060606@roeck-us.net> Date: Fri, 19 Feb 2016 17:15:20 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.5.1 MIME-Version: 1.0 In-Reply-To: <1455926991-15189-1-git-send-email-nm@ti.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Authenticated_sender: linux@roeck-us.net X-OutGoing-Spam-Status: No, score=-1.0 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bh-25.webhostbox.net X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - roeck-us.net X-Get-Message-Sender-Via: bh-25.webhostbox.net: authenticated_id: linux@roeck-us.net X-Authenticated-Sender: bh-25.webhostbox.net: linux@roeck-us.net X-Source: X-Source-Args: X-Source-Dir: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/19/2016 04:09 PM, Nishanth Menon wrote: > Thermal hook gpio_fan_get_cur_state is only interested in knowing > the current speed index that was setup in the system, this is > already available as part of fan_data->speed_index which is always > set by set_fan_speed. Using get_fan_speed_index is useful when we > have no idea about the fan speed configuration (for example during > fan_ctrl_init). > > When thermal framework invokes > gpio_fan_get_cur_state=>get_fan_speed_index via gpio_fan_get_cur_state > especially in a polled configuration for thermal governor, we > basically hog the i2c interface to the extent that other functions > fail to get any traffic out :(. > > Instead, just provide the last state set in the driver - since the gpio > fan driver is responsible for the fan state immaterial of override, the > fan_data->speed_index should accurately reflect the state. > > Fixes: b5cf88e46bad ("(gpio-fan): Add thermal control hooks") > > Reported-by: Tony Lindgren > Cc: Guenter Roeck > Cc: Eduardo Valentin > Signed-off-by: Nishanth Menon > --- Applied. Thanks, Guenter > Test logs from linus master v4.5-rc4-137-g23300f657594 > Without fix: http://paste.ubuntu.org.cn/3948618 > With Fix: http://paste.ubuntu.org.cn/3948617 > > drivers/hwmon/gpio-fan.c | 7 +------ > 1 file changed, 1 insertion(+), 6 deletions(-) > > diff --git a/drivers/hwmon/gpio-fan.c b/drivers/hwmon/gpio-fan.c > index 82de3deeb18a..685568b1236d 100644 > --- a/drivers/hwmon/gpio-fan.c > +++ b/drivers/hwmon/gpio-fan.c > @@ -406,16 +406,11 @@ static int gpio_fan_get_cur_state(struct thermal_cooling_device *cdev, > unsigned long *state) > { > struct gpio_fan_data *fan_data = cdev->devdata; > - int r; > > if (!fan_data) > return -EINVAL; > > - r = get_fan_speed_index(fan_data); > - if (r < 0) > - return r; > - > - *state = r; > + *state = fan_data->speed_index; > return 0; > } > >