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[2001:4c4e:24e4:9500:95:1480:ce1a:d54b]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-493eb670a41sm288828895e9.0.2026.07.12.10.44.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 12 Jul 2026 10:44:33 -0700 (PDT) From: Timur =?UTF-8?B?S3Jpc3TDs2Y=?= To: Alex Deucher , Lionso Alejandro Pacheco Vacacela Cc: amd-gfx@lists.freedesktop.org, regressions@lists.linux.dev, Fangzhi Zuo , Chuanyu Tseng , Wenjing Liu Subject: Re: [PATCH 1/2] drm/amd/display: Fix preferred link rate for NUTMEG Date: Sun, 12 Jul 2026 19:44:31 +0200 Message-ID: <2230825.9o76ZdvQCi@timur-max> In-Reply-To: <178379850751.8410.12007342378134020217@murena.io> References: <20260529090909.13206-1-timur.kristof@gmail.com> <178379850751.8410.12007342378134020217@murena.io> Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" On 2026. j=C3=BAlius 11., szombat 21:35:07 k=C3=B6z=C3=A9p-eur=C3=B3pai ny= =C3=A1ri id=C5=91 Lionso Alejandro=20 Pacheco Vacacela wrote: > Hi, >=20 > I independently hit this regression on a desktop Kaveri system and can > confirm this patch fixes it: >=20 > - AMD A10-7850K (Kaveri, DCE 8.1), MSI A68HM-E33, VGA monitor on the > onboard output (NUTMEG DP-to-VGA bridge) > - Debian kernel 7.1.3 (amdgpu.cik_support=3D1): VGA monitor receives no > signal from KMS takeover on; dmesg shows > "[drm] enabling link 2 failed: 15" (DC_FAIL_DP_LINK_TRAINING). > - Applying just this patch (1/2) on top of v7.1.3 restores VGA output > with DC enabled: the link trains, the CRTC comes up at 1360x768@60, > and the fix survived three consecutive reboots. >=20 > Tested-by: Lionso Alejandro Pacheco Vacacela Thank you for the testing! I would appreciate if you could verify that the second patch also works wel= l. >=20 > Two notes: >=20 > 1. The Fixes: tag references b74322eea36b, but that hash does not exist > in mainline =E2=80=94 it looks like an amd-staging-internal id. In Lin= us' > tree the offending commit is: >=20 > a62346043a89 ("drm/amd/display: Fix coding style issue") >=20 > It would be good to correct this before the patch is pushed so the > stable tooling can resolve the dependency. As far as I remember the regression hasn't made it upstream yet when I made= =20 the fix, so the hash didn't exist in Linus's tree yet. >=20 > 2. Since the offending commit shipped in v7.1, could this be annotated > Cc: stable@vger.kernel.org # 7.1.x (or nominated for 7.1.y once it > lands in mainline)? Every Kaveri/Kabini/Mullins system with a VGA > monitor loses display output on release kernels. Agreed. Alex can you please backport this to 7.1? Thanks & best regards, Timur