From mboxrd@z Thu Jan 1 00:00:00 1970 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 AC2FCC433FE for ; Tue, 7 Sep 2021 06:27:15 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 27D4360F92 for ; Tue, 7 Sep 2021 06:27:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 27D4360F92 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=weissschuh.net Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 26B2489301; Tue, 7 Sep 2021 06:27:05 +0000 (UTC) X-Greylist: delayed 505 seconds by postgrey-1.36 at gabe; Mon, 06 Sep 2021 22:05:48 UTC Received: from todd.t-8ch.de (todd.t-8ch.de [IPv6:2a01:4f8:c010:41de::1]) by gabe.freedesktop.org (Postfix) with ESMTPS id 7F17E89C6C for ; Mon, 6 Sep 2021 22:05:48 +0000 (UTC) From: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=weissschuh.net; s=mail; t=1630965441; bh=TBejuk5tqxeDF6kzvgEoVLlD9PzQKnYZHfHp2go1+m0=; h=From:To:Cc:Subject:Date:From; b=shQLHPvHG8+XyfIILO61kyyNG/BROBofAliqcMYmkCUaLfm8HZHAJviNKtZ7hMEmy DHiJe+9HFHypMP2UtGvEWf+3kxmPh/PNqAGqtVGOPpr7UbLPjKVJOobRUqoJEKMTVS 05/jvbADBFSRMZGQdtRjveq4E4vXVYzHIUKr1L0U= To: Lee Jones , Daniel Thompson , Jingoo Han , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org Cc: =?UTF-8?q?Thomas=20Wei=C3=9Fschuh?= , linux-kernel@vger.kernel.org Subject: [PATCH] backlight: propagate errors from get_brightness() Date: Mon, 6 Sep 2021 23:55:25 +0200 Message-Id: <20210906215525.15418-1-linux@weissschuh.net> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Mailman-Approved-At: Tue, 07 Sep 2021 06:27:04 +0000 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 --- drivers/video/backlight/backlight.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/drivers/video/backlight/backlight.c b/drivers/video/backlight/backlight.c index 537fe1b376ad..d681962f8509 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_warn(&bd->dev, + "Could not update brightness from device: errno = %d", + -brightness); + } mutex_unlock(&bd->ops_lock); backlight_generate_event(bd, reason); } base-commit: 79fad92f2e596f5a8dd085788a24f540263ef887 -- 2.33.0