From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19CFE1E3772; Mon, 21 Jul 2025 02:20:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753064449; cv=none; b=p5xXJY0MyjBlcaHWaEDAlojhZtuz9Jd9pOGYYjQ1OGrsU3CBV5MP59w3Im2ISJwYtJfnTGU0xeYn6YdMK5sBONnlzSIicQtGZdW2uaPKPIDPWb0B6cA2zF2NCTZb34OSmj8LkE4ZIP8PHfw0DWrZV8JXBOTmpBdVQnsow2Uozuk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753064449; c=relaxed/simple; bh=5jb/stM65I+0aJAhwVu6+xUzsAk79UL5kdDuxBOv+RQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=drP79X8mPGI4wkIVDTnMO2yr4jkDGo3YC/hTyBal+lTf9rgcBxt0v6E2Z5wLRFfK+QU4IBI/kIQxqcg6dlLpp7ULzSDQKDx+WVTIiCpr4VdcDluybf02qW7m5uSboHYDrcji2Sx66xFh69riVzgvyR63YggiW9p7kYJ2XU+fBJ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eBavyu9Y; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eBavyu9Y" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBB18C4CEE7; Mon, 21 Jul 2025 02:20:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753064448; bh=5jb/stM65I+0aJAhwVu6+xUzsAk79UL5kdDuxBOv+RQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=eBavyu9YloMUuBvSPrBaFBPIz8Ja0Y04OudwJ4HnqGLBVcn/jX4waGNzeN8A70QCC 8AriE4rCaeFZNiznwfNSYbvnXW1dLv8n6iUtMR208TVHb2h+wwe+4o0CNknpNjwRtE GKOSkLio5a9PQ8QXcVcxuoTCJSQbnm/kpeBToR6PZbPmFrhtuaJ7IFXRZvBhawpydQ uEpyi1Wpxz23XQPeDTy3WtgjyzFjBlJLaSK/9vi9VH5naFQNdlJdgouER5+p5br//i Wk+1PHuFTOILbYdT9ptYcN+OwF4d7w+rp1G5fjUySGqald8WwMS9wjJg7l+7C1+th9 Ke8VIO8hVd2FQ== Message-ID: <0f094c4b-d2a3-42cd-824c-dc2858a5618d@kernel.org> Date: Sun, 20 Jul 2025 21:20:46 -0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [REGRESSION] [PATCH v2] drm/amd/display: fix initial backlight brightness calculation To: Lauri Tirkkonen , linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org, amd-gfx@lists.freedesktop.org, Wayne Lin , Alex Deucher , Greg Kroah-Hartman References: Content-Language: en-US From: Mario Limonciello In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/20/25 7:59 PM, Lauri Tirkkonen wrote: > DIV_ROUND_CLOSEST(x, 100) returns either 0 or 1 if 0 division needs to be performed after the multiplication and not the > other way around, to properly scale the value. > > Fixes: 8b5f3a229a70 ("drm/amd/display: Fix default DC and AC levels") > Signed-off-by: Lauri Tirkkonen > Cc: stable@vger.kernel.org Thanks so much! Reviewed-by: Mario Limonciello > --- > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > index f58fa5da7fe5..8a5b5dfad1ab 100644 > --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c > @@ -4941,9 +4941,9 @@ amdgpu_dm_register_backlight_device(struct amdgpu_dm_connector *aconnector) > caps = &dm->backlight_caps[aconnector->bl_idx]; > if (get_brightness_range(caps, &min, &max)) { > if (power_supply_is_system_supplied() > 0) > - props.brightness = (max - min) * DIV_ROUND_CLOSEST(caps->ac_level, 100); > + props.brightness = DIV_ROUND_CLOSEST((max - min) * caps->ac_level, 100); > else > - props.brightness = (max - min) * DIV_ROUND_CLOSEST(caps->dc_level, 100); > + props.brightness = DIV_ROUND_CLOSEST((max - min) * caps->dc_level, 100); > /* min is zero, so max needs to be adjusted */ > props.max_brightness = max - min; > drm_dbg(drm, "Backlight caps: min: %d, max: %d, ac %d, dc %d\n", min, max,