{"id":806756,"url":"http://patchwork.ozlabs.org/api/1.0/patches/806756/?format=json","project":{"id":38,"url":"http://patchwork.ozlabs.org/api/1.0/projects/38/?format=json","name":"Linux PWM development","link_name":"linux-pwm","list_id":"linux-pwm.vger.kernel.org","list_email":"linux-pwm@vger.kernel.org","web_url":"","scm_url":"","webscm_url":""},"msgid":"<20170828200033.40673-1-dbasehore@chromium.org>","date":"2017-08-28T20:00:33","name":"pwm_bl: Fix overflow condition","commit_ref":null,"pull_url":null,"state":"superseded","archived":false,"hash":"e89c504d64ac541b8b43cff09c0cc5c2af57e342","submitter":{"id":20364,"url":"http://patchwork.ozlabs.org/api/1.0/people/20364/?format=json","name":"dbasehore .","email":"dbasehore@chromium.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pwm/patch/20170828200033.40673-1-dbasehore@chromium.org/mbox/","series":[{"id":250,"url":"http://patchwork.ozlabs.org/api/1.0/series/250/?format=json","date":"2017-08-28T20:00:33","name":"pwm_bl: Fix overflow condition","version":1,"mbox":"http://patchwork.ozlabs.org/series/250/mbox/"}],"check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/806756/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":["ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=linux-pwm-owner@vger.kernel.org;\n\treceiver=)","ozlabs.org;\n\tdkim=fail reason=\"signature verification failed\" (1024-bit key;\n\tunprotected) header.d=chromium.org header.i=@chromium.org\n\theader.b=\"lyaIBld1\"; dkim-atps=neutral"],"Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xh2gr5WjMz9s7c\n\tfor ;\n\tTue, 29 Aug 2017 06:00:40 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751192AbdH1UAj (ORCPT );\n\tMon, 28 Aug 2017 16:00:39 -0400","from mail-pg0-f44.google.com ([74.125.83.44]:34617 \"EHLO\n\tmail-pg0-f44.google.com\" rhost-flags-OK-OK-OK-OK) by vger.kernel.org\n\twith ESMTP id S1750735AbdH1UAj (ORCPT\n\t); Mon, 28 Aug 2017 16:00:39 -0400","by mail-pg0-f44.google.com with SMTP id y15so4396616pgc.1\n\tfor ; Mon, 28 Aug 2017 13:00:39 -0700 (PDT)","from exogeni.mtv.corp.google.com\n\t([2620:0:1000:1600:211e:5908:95bc:4888])\n\tby smtp.gmail.com with ESMTPSA id\n\th4sm2085689pfg.165.2017.08.28.13.00.37\n\t(version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);\n\tMon, 28 Aug 2017 13:00:37 -0700 (PDT)"],"DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=chromium.org; s=google;\n\th=from:to:cc:subject:date:message-id;\n\tbh=L0ux5QgapmoQxNzqbbU+hBhbe2F0u6S4LRjCwbBqNOs=;\n\tb=lyaIBld1RohR9+981IqWKhBZ1c0/LEhZYkvHGBLzKb1J/+MzFTF9242wlrnvGrIH8H\n\tQFiy8ltEog/GHFybGcXiH3+SvoXhJ6zKlcZa5eXUjFLXtjd004Ota4UtiXqdBv4n1+S6\n\tYmwgW1pWH1qRG54voQ+UYIX/1GYus6LABb+1c=","X-Google-DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/relaxed;\n\td=1e100.net; s=20161025;\n\th=x-gm-message-state:from:to:cc:subject:date:message-id;\n\tbh=L0ux5QgapmoQxNzqbbU+hBhbe2F0u6S4LRjCwbBqNOs=;\n\tb=JobuFebF10I3wqNY9DteX1rH+8FedOg7l1ahtsTOFf8TroBZz5Rr3PTdaEjXAJMmtc\n\tIVK+lFAgnpDMNoHtaaJRr2OX0YkRuDC7hnZ0jjuN0VcHMIl0YO40MRRVWY020bJVB1uD\n\tzQbwX/2HHPGjofctBoxawf6lFNfs6yNYtg4WY3DWb3UYLnvS3T/iXJds+ZTmGIwF34ux\n\tTgFjLm/rYVNEDDSw0FSNK+wxCDA91yW+iQw95VG0rs2nvZ/Wn6v12fn3WJdbADu8JTV1\n\tvt9BDWzgz1s6yDx2dI6OREmxVa/A33Qo0fichfyLKF//hK3130OmNJT3xORQEhPyIIPg\n\tRpZw==","X-Gm-Message-State":"AHYfb5h+/zM56sZpJl8Qf5vj3I80QBkxPkDJNayVMj7aOkphD8v2wOz9\n\tzhy9HnTQETuY7osH","X-Received":"by 10.84.194.195 with SMTP id h61mr2031228pld.335.1503950438838; \n\tMon, 28 Aug 2017 13:00:38 -0700 (PDT)","From":"Derek Basehore ","To":"linux-kernel@vger.kernel.org","Cc":"thierry.reding@gmail.com, jingoohan1@gmail.com,\n\tlee.jones@linaro.org, linux-pwm@vger.kernel.org,\n\tDerek Basehore ","Subject":"[PATCH] pwm_bl: Fix overflow condition","Date":"Mon, 28 Aug 2017 13:00:33 -0700","Message-Id":"<20170828200033.40673-1-dbasehore@chromium.org>","X-Mailer":"git-send-email 2.14.1.342.g6490525c54-goog","Sender":"linux-pwm-owner@vger.kernel.org","Precedence":"bulk","List-ID":"","X-Mailing-List":"linux-pwm@vger.kernel.org"},"content":"This fixes and overflow condition that happens with a high value of\nbrightness-levels-scale by using a 64-bit variable. The issue would\nprevent a range of higher brightness levels from being set.\n\nSigned-off-by: Derek Basehore \n---\n drivers/video/backlight/pwm_bl.c | 7 +++++--\n 1 file changed, 5 insertions(+), 2 deletions(-)","diff":"diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c\nindex 76311ec5e400..e7ffd2108acf 100644\n--- a/drivers/video/backlight/pwm_bl.c\n+++ b/drivers/video/backlight/pwm_bl.c\n@@ -88,14 +88,17 @@ static void pwm_backlight_power_off(struct pwm_bl_data *pb)\n static int compute_duty_cycle(struct pwm_bl_data *pb, int brightness)\n {\n \tunsigned int lth = pb->lth_brightness;\n-\tint duty_cycle;\n+\ts64 duty_cycle;\n \n \tif (pb->levels)\n \t\tduty_cycle = pb->levels[brightness];\n \telse\n \t\tduty_cycle = brightness;\n \n-\treturn (duty_cycle * (pb->period - lth) / pb->scale) + lth;\n+\tduty_cycle *= pb->period - lth;\n+\tdo_div(duty_cycle, pb->scale);\n+\n+\treturn duty_cycle + lth;\n }\n \n static int pwm_backlight_update_status(struct backlight_device *bl)\n","prefixes":[]}