From patchwork Tue Sep 7 12:47:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= X-Patchwork-Id: 507701 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B22A4C433EF for ; Tue, 7 Sep 2021 12:48:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 97CF160724 for ; Tue, 7 Sep 2021 12:48:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343949AbhIGMtI (ORCPT ); Tue, 7 Sep 2021 08:49:08 -0400 Received: from todd.t-8ch.de ([159.69.126.157]:39879 "EHLO todd.t-8ch.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231600AbhIGMtH (ORCPT ); Tue, 7 Sep 2021 08:49:07 -0400 From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=weissschuh.net; s=mail; t=1631018878; bh=ATKYi2Vk5p0hBeuPNHEODB9n/mjvnxJq3rBPTJFZlp0=; h=From:To:Cc:Subject:Date:From; b=IooRD0Vl+15Z32+h4hNQYZl9xacLWEALyLzlP1IV3rSc3BA5DGwm9dyDsQP4+qvxv 8CDNM4tcj5LCSs/cslgzcxtYRh2FCtt3yxUtUD4/rZNyJfHcjH2zrQyvB2lxxhyJjv N8AcFOtaiaHs3r8Rjm2wZIxWm2JCbFZXc3kiFgfo= To: Lee Jones , Daniel Thompson , Jingoo Han , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org Cc: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= , linux-kernel@vger.kernel.org Subject: [PATCH v2] backlight: propagate errors from get_brightness() Date: Tue, 7 Sep 2021 14:47:51 +0200 Message-Id: <20210907124751.6404-1-linux@weissschuh.net> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org backlight.h documents "struct backlight_ops->get_brightness()" to return a negative errno on failure. So far these errors have not been handled in the backlight core. This leads to negative values being exposed through sysfs although only positive values are documented to be reported. Signed-off-by: Thomas Weißschuh --- v1: https://lore.kernel.org/dri-devel/20210906215525.15418-1-linux@weissschuh.net/ v1 -> v2: * use dev_err() instead of dev_warn() (Daniel Thompson) * Finish logging format string with newline (Daniel Thompson) * Log errno via dedicated error pointer format (Daniel Thompson) drivers/video/backlight/backlight.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) base-commit: 79fad92f2e596f5a8dd085788a24f540263ef887 diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index 537fe1b376ad..4658cfb75aa2 100644 --- a/drivers/video/backlight/backlight.c +++ b/drivers/video/backlight/backlight.c @@ -292,10 +292,13 @@ static ssize_t actual_brightness_show(struct device *dev, struct backlight_device *bd = to_backlight_device(dev); mutex_lock(&bd->ops_lock); - if (bd->ops && bd->ops->get_brightness) - rc = sprintf(buf, "%d\n", bd->ops->get_brightness(bd)); - else + if (bd->ops && bd->ops->get_brightness) { + rc = bd->ops->get_brightness(bd); + if (rc >= 0) + rc = sprintf(buf, "%d\n", rc); + } else { rc = sprintf(buf, "%d\n", bd->props.brightness); + } mutex_unlock(&bd->ops_lock); return rc; @@ -381,9 +384,18 @@ ATTRIBUTE_GROUPS(bl_device); void backlight_force_update(struct backlight_device *bd, enum backlight_update_reason reason) { + int brightness; + mutex_lock(&bd->ops_lock); - if (bd->ops && bd->ops->get_brightness) - bd->props.brightness = bd->ops->get_brightness(bd); + if (bd->ops && bd->ops->get_brightness) { + brightness = bd->ops->get_brightness(bd); + if (brightness >= 0) + bd->props.brightness = brightness; + else + dev_err(&bd->dev, + "Could not update brightness from device: %pe\n", + ERR_PTR(brightness)); + } mutex_unlock(&bd->ops_lock); backlight_generate_event(bd, reason); }