From nobody Sat Feb 14 05:36:22 2026 Received: from st43p00im-zteg10072001.me.com (st43p00im-zteg10072001.me.com [17.58.63.167]) (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 E8DC73BBF6 for ; Wed, 15 May 2024 19:20:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=17.58.63.167 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715800820; cv=none; b=SRd6tQ64rKj1MQw2mchRyjnrWJ4ltwFyk4B5dNpaWf99/jPXQeSK0moI8PCTG49ONwlHi+HBHJUj0GExkMwtsHSMdUg7qXnko6PGaz7YWaB1suUbYyKTqr16Pp7HtqIaaUIZAx36/dI2ONI8Ro+BXnVoOcRZICntFKESLKHKZ50= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715800820; c=relaxed/simple; bh=Prmzm/RN0BcYmaIiUK8WwBAZ7FwXUveOP6CKkBYomkE=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=CHdwZLo2ZT3UuhkIn9jG0ulXF+TQhbwqcY5aOvC7svaKQavKal0I7OdY10yrA3V8JvIp3YwmI2gRK/624JF0NIyz94vcPJSsUPxzseYNrjsSNi5x+L5hzuUd478YrSV90vSYdnL21YFFHJU0Puipg1vfi8nq3t6jBhEyVz5ZF7M= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=icloud.com; spf=pass smtp.mailfrom=icloud.com; dkim=pass (2048-bit key) header.d=icloud.com header.i=@icloud.com header.b=C3WezpJK; arc=none smtp.client-ip=17.58.63.167 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=icloud.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=icloud.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=icloud.com header.i=@icloud.com header.b="C3WezpJK" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=icloud.com; s=1a1hai; t=1715800817; bh=gChLto0wuBmBkw+d7DrIrxrJwuCOppo9zmpl1lXbdD8=; h=From:To:Subject:Date:Message-Id:MIME-Version; b=C3WezpJKXYp1V0bqCt0aNOoC9wj6JqDMqgkHD2VNIDZqvy8Gr/TCb8nbCjit+fuKm /TwfGTCWMRiTjQ17PreSa4pM1mez7aOngR/ayALjbaZCCNs4rdk/EpuqX6Fs6Ln7J5 TILmtLomiH0OOtiysvqoBvY4nhFTowJVHYZGqP0oSskL09d1JhuRUCWkUrJQSQYl6t 3EYO2A3LNnFLcQK+nBrfeJwM0VpNOGa4hrcPcwdFZPdqU1RuQpJxJQ6rYsarwVWgQ4 ChLsLfywXTN1416GoGw2gZO7zvKza3Jsi1xqkVnpPIXDrbYvEeJIcz/1hk3BugMbvx uveFWbFI/kWyg== Received: from kendalls-iMac.lan (st43p00im-dlb-asmtp-mailmevip.me.com [17.42.251.41]) by st43p00im-zteg10072001.me.com (Postfix) with ESMTPSA id 72CEF120E52; Wed, 15 May 2024 19:20:17 +0000 (UTC) From: Kendall Smith To: amd-gfx@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org, Kendall Smith Subject: [PATCH] drm/radeon: initialize atom DIG backlight for iMac12,1 and iMac12,2 with Radeon 6750M Date: Wed, 15 May 2024 15:20:09 -0400 Message-Id: <20240515192009.14362-1-kendallsm2@icloud.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Proofpoint-GUID: vg2uwT33525UOzvB4dxOGeO5YaER4aZP X-Proofpoint-ORIG-GUID: vg2uwT33525UOzvB4dxOGeO5YaER4aZP X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.1039,Hydra:6.0.650,FMLib:17.11.176.26 definitions=2024-05-15_12,2024-05-15_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 clxscore=1011 phishscore=0 mlxlogscore=999 bulkscore=0 adultscore=0 suspectscore=0 spamscore=0 malwarescore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2308100000 definitions=main-2405150138 X-Apple-Remote-Links: v=1;h=KCk=;charset=UTF-8 Content-Type: text/plain; charset="utf-8" If a Radeon 6750M GPU from an iMac12,1 is installed into an iMac 12,2, ther= e is no backlight device initialized during boot. Everything else is functi= onal, but the display brightness cannot be controlled. There are no directo= ries present in /sys/class/backlight after booting. A simple one line modif= ication to an if statement fixes this issue by initializing the radeon back= light device for an iMac12,2 as well if it has a 6750M. After the patch, br= ightness can be controlled and radeon_bl0 is present in /sys/class/backligh= t. This was tested by compiling the latest kernel with and without the patc= h. Signed-off-by: Kendall Smith --- drivers/gpu/drm/radeon/atombios_encoders.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/r= adeon/atombios_encoders.c index 2bff0d9e20f5..7b11674f5d45 100644 --- a/drivers/gpu/drm/radeon/atombios_encoders.c +++ b/drivers/gpu/drm/radeon/atombios_encoders.c @@ -201,7 +201,7 @@ void radeon_atom_backlight_init(struct radeon_encoder *= radeon_encoder, */ if ((rdev->pdev->subsystem_vendor =3D=3D PCI_VENDOR_ID_APPLE) && (rdev->pdev->device =3D=3D 0x6741) && - !dmi_match(DMI_PRODUCT_NAME, "iMac12,1")) + !(dmi_match(DMI_PRODUCT_NAME, "iMac12,1") || dmi_match(DMI_PRODUCT_NA= ME, "iMac12,2"))) return; =20 if (!radeon_encoder->enc_priv) --=20 2.34.1