From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f41.google.com (mail-wr1-f41.google.com [209.85.221.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D43A663D0 for ; Sat, 14 Jan 2023 14:53:00 +0000 (UTC) Received: by mail-wr1-f41.google.com with SMTP id b5so2369637wrn.0 for ; Sat, 14 Jan 2023 06:53:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:from:to:cc:subject:date:message-id :reply-to; bh=TNfS9hq3Jd9+y3no15GrHwb3oIxtxOEzkgxgD6diI+c=; b=H7GjTackpwpq5bsoAP3JDZ00CWELzIhssuFXhH7+tp8C+iZsGDGoWUJ3dTIjcKaS0K A9tUnWAFA+hON5CBBJILnJ+hBvqLMwG/4L7/sketgMLFmSY0iQt0W577V9B1dQ7QESHJ JcTi9mnC7GyWOybsUCuKEZILkwSfvv32laZV5iANUiQ75wI9asQgrhUS5vlvtR0XqOzU 2ewkXKhlUtVCINlZBoMCU2X/xOnHXbt/W6S476WgnD945zuogIPCsqgaLoqr2InkuDFH YJQUwWXn8AYYqR4eJqUogk8+YnaND+jphRLW7vjwXbjs6Fh81PuE2oiI2N9uKRucp0t9 SD8A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:sender:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=TNfS9hq3Jd9+y3no15GrHwb3oIxtxOEzkgxgD6diI+c=; b=ig7vvR3Gr7ZKDEkhkAXDDw/UGdvKkc+ksb5Ps+Dv5rz+kXXPpP+yNKYK5+IlFF7TWp SIRNs2WLZQIOTiRnROYJq2Y/Ri05Srb8J4dItM3fm3diNKfw8dzXak8g1g5/eIh/BMin Wlenee7v+jIZeHFCEucvKW49esktsJ31S6FUsw7eKnpjI0Y7c3N44SaPQpWW7egfOT1K 36Zyylnj+vcrBTPRRy8JlU6BAKvkYAFrXnIuZHIf9Oh0l1xb62iWLNvBnu56t+ZcegOh Qqj2Y4GowgQZdAq25JSQ7A/bCjXo7pNkQvzBXfjv5feW5MjYAp9RFbabYp/RMrBKbx1n aJ+Q== X-Gm-Message-State: AFqh2kpQO2FSF728AkQ3jw6IFpF0jmPCVHbdP87ro1hs1EfqMQ6AbxQa 9YoFdzqJrZvFAnDZsoHAeuY= X-Google-Smtp-Source: AMrXdXsAjsyC1Cj8qg8J8+fykF7Jkm828W2yIULpeTwffczuG9I6Lh88g/8lLArTQr2UaecUeRxmJw== X-Received: by 2002:adf:ef84:0:b0:2bd:e220:6b9 with SMTP id d4-20020adfef84000000b002bde22006b9mr4544594wro.38.1673707978885; Sat, 14 Jan 2023 06:52:58 -0800 (PST) Received: from eldamar.lan (c-82-192-242-114.customer.ggaweb.ch. [82.192.242.114]) by smtp.gmail.com with ESMTPSA id t10-20020a5d534a000000b00272c0767b4asm21849954wrv.109.2023.01.14.06.52.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 14 Jan 2023 06:52:58 -0800 (PST) Sender: Salvatore Bonaccorso Received: by eldamar.lan (Postfix, from userid 1000) id 829E7BE2DE0; Sat, 14 Jan 2023 15:52:57 +0100 (CET) Date: Sat, 14 Jan 2023 15:52:57 +0100 From: Salvatore Bonaccorso To: Greg KH Cc: Matthew Fahner , stable@vger.kernel.org, regressions@lists.linux.dev Subject: Re: Second Monitor Issue on Kernel 6.1.5 Message-ID: References: Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Hi, On Sat, Jan 14, 2023 at 07:56:50AM +0100, Greg KH wrote: > On Fri, Jan 13, 2023 at 11:58:47PM -0500, Matthew Fahner wrote: > > Hello, > > > > I'm running Ubuntu 20.10 and experienced a regression when trying > > kernel 6.1.5 that was not present in previous kernels such as 6.0.19 > > or 6.0.9 > > > > I have two monitors attached using DisplayPort MST (daisy chaining the > > displays). > > > > Normally, this works without issue and both monitors are detected and > > display properly. > > > > With kernel 6.1.5, the second monitor (the monitor that's not directly > > connected to the computer) was detected but would not display. I > > didn't spend much time troubleshooting the issue and instead reverted > > to 6.0.19 where it again worked without issue. The first monitor > > worked without issue. > > > > Let me know what steps I can take to help identify the root cause. > > Can you use 'git bisect' to track down the offending commit? Not the reporter, but I suspect this is https://gitlab.freedesktop.org/drm/amd/-/issues/2171 . Matthew can you verify this matches? There is as well context on this issue on this thread: https://lore.kernel.org/stable/8502e5d8-8444-e256-54f3-0c488b54686a@amd.com/ FWIW, we had a similar bugreport downstream in Debian: https://bugs.debian.org/1028451 Regards, Salvatore