From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756366AbbJAIBO (ORCPT ); Thu, 1 Oct 2015 04:01:14 -0400 Received: from eusmtp01.atmel.com ([212.144.249.243]:49635 "EHLO eusmtp01.atmel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755334AbbJAIBM (ORCPT ); Thu, 1 Oct 2015 04:01:12 -0400 Subject: Re: [PATCH] Revert "backlight: pwm: Handle EPROBE_DEFER while requesting the PWM" To: Robert Jarzmik , Thierry Reding , , Boris BREZILLON , Alexandre Belloni References: <1443295482-18687-1-git-send-email-robert.jarzmik@free.fr> <87bncjemdk.fsf@belgarion.home> CC: Jingoo Han , Lee Jones , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , , From: Nicolas Ferre Organization: atmel Message-ID: <560CE816.1060307@atmel.com> Date: Thu, 1 Oct 2015 10:00:22 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: <87bncjemdk.fsf@belgarion.home> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 8bit X-Originating-IP: [10.161.30.18] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Well, as I answered on the linux-pwm mailing-list (I was not in copy) here: http://article.gmane.org/gmane.linux.pwm/2744 I wonder if it's not easier to fix the platforms and add the pwm tables... 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. Bye, -- Nicolas Ferre