From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f45.google.com (mail-pj1-f45.google.com [209.85.216.45]) (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 3E0652D8799 for ; Mon, 26 Jan 2026 20:49:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.45 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769460565; cv=none; b=IQ5FpDH3zkLyQ6LF1nfOOLKPBbulKPqA2P0cYVPa3+J9cNAhaTulKF8F0p3iMJt2noevtFrnQsuk18+Oeb3OLZs9XPq9L7bo8NML3x54afu0FaQkBCUVC3CsGW5jv11NsN0Kcxn/nSKgFUgcsnMoEfVfJqngf3qfS8ULgPcQzLM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769460565; c=relaxed/simple; bh=VHg4i6s9HZEfjPjpMQaKYLGEBq/QjP3xamzF/YCynPE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=n3enDq787a4o0xs+WGuudMiS7ALqXEQYn+krSkOGmaGPaSYwMau6ffB/J6TAvAfyAFkMlrVDAxRljgORT633nhBkWS6xsLgGyJimGt79hZccR46tHcTjwlCjJPPj+F/4yOgYHf1q12PoaKr6cS7cmkJI0944e6TztW79E0PDW84= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=MMFbRLZM; arc=none smtp.client-ip=209.85.216.45 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="MMFbRLZM" Received: by mail-pj1-f45.google.com with SMTP id 98e67ed59e1d1-350fe1f8ea3so2380926a91.2 for ; Mon, 26 Jan 2026 12:49:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1769460563; x=1770065363; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=DgBDIJIrUHpJ6j6lR+sPmz5sI1yJjso51mAmb29uJAg=; b=MMFbRLZMVkJsiyahNE+Mi6hR93Q6GOxOPuDcwZoSOEb9O1Y3RlGtZymuoevkBU9299 fDsHdq/pfFrHef56CNM2XaSAqNhHFeO/w2MBnjz4VndcnJJzix+YTrvr+7rHkFFKxQ6A DQkmx91vqOZ4vm7qEGjEBq5UbjMzRojecL9lF5XN+/IaapS1v51L9nbxJLFzPO92vIWH /0/csXkrX2x0rXZTqP9FOJMQ4Sc+NoFwGPwGEWsR5+0mhtAwqkxUH6lFmtsRCwtGTNPa VmMzhvzjYnbL1NbZixRJbR3xNjXEWhLEbGp1/D2+zdRgRL5CGLZabt0Wrphh7vcb3rx/ 40HQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1769460563; x=1770065363; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to; bh=DgBDIJIrUHpJ6j6lR+sPmz5sI1yJjso51mAmb29uJAg=; b=HFDJOXfAKwzcIz1nmCA/pR65VV2vK0JK2z/P1IoJdwgbs2u89TPWUPHZuuO5eMxMRz QT8TLtsh5q8aaVonmQT/fkJdch6sP39A4Tgo4RQfthj6yf+fwcsLseDcWVGTvpo+k0fL BiSklmXbaXW1gXpImETWjCDK48CZiaE6yXUR2xqKQnQn6mfMMZ7EKxRCxpKNRf0S4J/4 6IG3q9X9jpZbuwE2XrP6OGwZ7JNbej5DR5TFD8j9REfJJW6OrivUL6MuI+iZHonlQuIf kBKPUKOLMtItVKE/7Ea23OT3Po2ojjNN0EYLC+St4/Tuq7FS+A8aHtvFG+14+IXCn8G5 EYSg== X-Forwarded-Encrypted: i=1; AJvYcCXG81l1BjgRzafsUfur2dAX0ysKUYvnXFF7MsdK6CWAr1oT9Ozln4OB1l/+/B6aX7GK2jKaL2dkO2g3/Oc=@vger.kernel.org X-Gm-Message-State: AOJu0YyY3Q8GKJCyPNxt/P+lzN5baqBCHEgIrha2zuyiUzuF+5xZwypr ZR7KpaDQrhoWXm8MTZeRq//EkaSXWmW3NUJxt7j/Or6LFgnzhEp48RU= X-Gm-Gg: AZuq6aIAU+2qAneOYkgr9tWNx+5yzp06ISVmWwGtdIuXdew9bSg9Hpnfu4+yIZiyj4V NmN7D3umzooPM0/31A7+9/mKHes2wGXrccaVa3bPepteKfk9n+uVz3jmSvG99B6YO2sckHSIRhy U6mMPW+RjYG/EWPq+lP04UZo2mb2uV8gQ4bfwFqry2mR/qUjH9OG0GOPw+JlNH0+uGqvJX+NSUh PAcrI5tNAwUJD+UAfQGLAIAl99MVmBlk1ePk1zcKJ5gctqw0lUq1Ze1hwtJIszjTZMz4VIoRRPX pVnavJ7eMU3lfE9aYmAPkEDBnXWyERpkeZd5ARzLlinikmbDYfnCHcWXxFxcSUFcdJSZBWYeunY gLUr1pNt2UbMAdyr8d3SH1o2Jx7jhxKncj/lgAQnhhmSDXgduOC9N4UyOgorJVej89mQmF1SxHn DiPrWsTETOC/nMkMJTKg8qPi0jaA== X-Received: by 2002:a17:90b:350e:b0:341:2b78:61b8 with SMTP id 98e67ed59e1d1-353c416b90cmr5425981a91.20.1769460563371; Mon, 26 Jan 2026 12:49:23 -0800 (PST) Received: from at.. ([171.61.166.126]) by smtp.gmail.com with ESMTPSA id d2e1a72fcca58-82339095c85sm5470337b3a.67.2026.01.26.12.49.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Jan 2026 12:49:22 -0800 (PST) From: Atharva Tiwari To: jani.nikula@linux.intel.com Cc: airlied@gmail.com, atharvatiwarilinuxdev@gmail.com, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, joonas.lahtinen@linux.intel.com, linux-kernel@vger.kernel.org, rodrigo.vivi@intel.com, simona@ffwll.ch, tursulin@ursulin.net, ville.syrjala@linux.intel.com Subject: Re: [PATCH 2/2] drm/i915/display: Disable display for iMac's Date: Mon, 26 Jan 2026 20:49:15 +0000 Message-ID: <20260126204915.1324-1-atharvatiwarilinuxdev@gmail.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Rendering and display are quite separate in the hardware and in the > driver. Perhaps you do not mean "rendering" here? Perhaps it can be used > for rendering but not display? Yeah, it can be used for rendering but not display, sorry for the wording. > Okay, so perhaps there's no eDP connected. But what about the other > connectors on the iGPU? What about everything else in the display > hardware? You cant use the iGPU to drive the display on any hardware (including external displays). > If you can figure out that it's specifically link training that fails (a > dmesg would be useful to show this) there clearly is display hardware, > right? As said the iGPU cant drive the display on all monitors (even on macOS), but still heres the dmesg before this patch: [ 5.095489] i915 0000:00:02.0: [drm] Found cometlake (device ID 9bc8) integrated display version 9.00 stepping N/A [ 5.096061] i915 0000:00:02.0: [drm] VT-d active for gfx access [ 5.096102] i915 0000:00:02.0: [drm] Using Transparent Hugepages [ 5.099214] i915 0000:00:02.0: Invalid PCI ROM header signature: expecting 0xaa55, got 0xffff [ 5.099217] i915 0000:00:02.0: [drm] Failed to find VBIOS tables (VBT) [ 5.099324] i915 0000:00:02.0: vgaarb: VGA decodes changed: olddecodes=io+mem,decodes=none:owns=io+mem [ 5.100960] i915 0000:00:02.0: [drm] Finished loading DMC firmware i915/kbl_dmc_ver1_04.bin (v1.4) [ 5.832214] i915 0000:00:02.0: [drm] [ENCODER:105:DDI A/PHY A] failed to retrieve link info, disabling eDP [ 5.835756] i915 0000:00:02.0: [drm] Registered 3 planes with drm panic [ 6.428455] i915 0000:00:02.0: [drm] Cannot find any crtc or sizes [ 6.722404] i915 0000:00:02.0: [drm] Cannot find any crtc or sizes > There's at least three levels where this could be handled, depending on > details: > > - Display probe (the patch at hand). Assumes there's no display > hardware, at all. The driver doesn't touch the hardware, which > continues to consume power, it's not put in low power states. Not > optimal if there actually is display hardware. > > - Display disable. See intel_display_device_enabled(). The driver takes > over the hardware, puts it to sleep, but prevents all connectors from > being connected. > > - eDP disable. Add a quirk somewhere to enforce eDP is disconnected, but > other connectors can be used. The main reason I sent this patch is that after i915 trys to probe the display, the dGPU (amdgpu) is no longer able to detect the internal display, resulting in a black screen. > It would be quite useful to indicate the PCI ID of the device in > question. 00:02.0 VGA compatible controller [0300]: Intel Corporation CometLake-S GT2 [UHD Graphics 630] [8086:9bc8] (rev 03) (prog-if 00 [VGA controller]) Subsystem: Apple Inc. CometLake-S GT2 [UHD Graphics 630] [106b:ffff]