From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754136AbbJARpB (ORCPT ); Thu, 1 Oct 2015 13:45:01 -0400 Received: from smtp09.smtpout.orange.fr ([80.12.242.131]:41293 "EHLO smtp.smtpout.orange.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753507AbbJARo7 convert rfc822-to-8bit (ORCPT ); Thu, 1 Oct 2015 13:44:59 -0400 X-ME-Helo: belgarion X-ME-Auth: amFyem1pay5yb2JlcnRAb3JhbmdlLmZy X-ME-Date: Thu, 01 Oct 2015 19:44:56 +0200 X-ME-IP: 86.199.64.143 From: Robert Jarzmik To: Nicolas Ferre , Boris BREZILLON , Thierry Reding Cc: , Alexandre Belloni , Jingoo Han , Lee Jones , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , , Subject: Re: [PATCH] Revert "backlight: pwm: Handle EPROBE_DEFER while requesting the PWM" References: <1443295482-18687-1-git-send-email-robert.jarzmik@free.fr> <87bncjemdk.fsf@belgarion.home> <560CE816.1060307@atmel.com> X-URL: http://belgarath.falguerolles.org/ Date: Thu, 01 Oct 2015 19:39:46 +0200 In-Reply-To: <560CE816.1060307@atmel.com> (Nicolas Ferre's message of "Thu, 1 Oct 2015 10:00:22 +0200") Message-ID: <8737xuebdp.fsf@belgarion.home> User-Agent: Gnus/5.130008 (Ma Gnus v0.8) Emacs/24.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nicolas Ferre writes: > Le 30/09/2015 21:29, Robert Jarzmik a écrit : >> Robert Jarzmik writes: >> >>> This reverts commit 68feaca0b13e453aa14ee064c1736202b48b342f. >>> This commit breaks legacy platforms, for which : >>> (a) no pwm table is added (legacy platforms) >>> (b) in this case, in pwm_get(), pmw_lookup_list is empty, and therefore >>> chosen == NULL, and therefore pwm_get() returns NULL, and pwm_get() >>> returns -EPROBE_DEFER >>> (c) as a consequence, this code is unreachable in pwm_bl.c : >>> if (IS_ERR(pb->pwm)) { >>> ret = PTR_ERR(pb->pwm); >>> dev_info(&pdev->dev, "%s:%d(): %d\n", __func__, __LINE__, ret); >>> if (ret == -EPROBE_DEFER) >>> goto err_alloc; >>> >>> dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); >>> pb->legacy = true; >>> pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); >>> >>> As this code is unreachable, all legacy platforms relying on pwm_id are >>> broken, amongst which pxa have been tested as broken. >>> >>> Signed-off-by: Robert Jarzmik >> Thierry, would you have a look please ? >> As I said before, all legacy platform relying on pwm_id are broken. I'd like to >> be sure this lands in the next -rc series. > > Otherwise, Boris proposed this fix: > 8<----------------------------------------------------------- > diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c > index eff379b..00483d4 100644 > --- a/drivers/video/backlight/pwm_bl.c > +++ b/drivers/video/backlight/pwm_bl.c > @@ -273,15 +273,15 @@ static int pwm_backlight_probe(struct platform_device *pdev) > pb->pwm = devm_pwm_get(&pdev->dev, NULL); > if (IS_ERR(pb->pwm)) { > ret = PTR_ERR(pb->pwm); > - if (ret == -EPROBE_DEFER) > - goto err_alloc; > > dev_err(&pdev->dev, "unable to request PWM, trying legacy API\n"); > pb->legacy = true; > pb->pwm = pwm_request(data->pwm_id, "pwm-backlight"); > if (IS_ERR(pb->pwm)) { > dev_err(&pdev->dev, "unable to request legacy PWM\n"); > - ret = PTR_ERR(pb->pwm); > + if (ret != -EPROBE_DEFER) > + ret = PTR_ERR(pb->pwm); > + > goto err_alloc; > } > } > > which is not tested and may add an extra non-valid error log. Now it is tested, and it works correctly AFAICS. So could you or Borris post this patch, with : Fixes: 68feaca0b13e ("backlight: pwm: Handle EPROBE_DEFER while requesting the PWM") Tested-by: Robert Jarzmik That would be a good replacement for the revert. Maybe stable tree should be joined too ... Cheers. -- Robert