From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ixit.cz (ixit.cz [84.42.129.46]) (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 BCECB49B44F; Thu, 17 Sep 2026 22:10:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=84.42.129.46 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789683006; cv=none; b=IuzpmurS6p6nRTBBQ+vfNT3dgr1chGawFyvL9oJ5cezAdJA0EHYxq+YGtTeyK3Uq3b1vVz7ZbbStDSv1R6ceTu7KXnfw/0D2d8cY/nTQdl7X6DV8JxpzrgDjpPRqD6mUnpsS2mXT5fyMRbnmCoAbS9CWUm9zuU9YB84GxBf5W74= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789683006; c=relaxed/simple; bh=mCpl6QvIFmZxeLmdoMUfxKfCOG+tsTZ73OkJqmhqtOQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hxPZZFznieh2Pq7P0oVtpVxezet6ZQ7T1tlM3YdxKXUXhIWUp5TmNWSY40WkKw07bVniRo+bLNczotDVHDApeNOsvSlVKWID9044gDGM1zaaIbph3dc+EwTzhiTCDIFrQ/+k3MaSzZvOsAvcJ0gyqsdO2+KZ9WZRTgOIOX6UJzs= ARC-Authentication-Results:i=1; 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bh=w542DP45Fab9ijkwZo5VGiQ54TLBbOLVPnee5WaS4as=; b=j/4Vg1orluWplRkwEdZE6ATs2D6kCLuIcSMCfQb4oZH84n6A28CrKfsBTk/15uGjBpcn6J rRhd5wcHRuGcMPiNfXY5JamS9sRF9pBT+eBbu9w7F8jT7O2bBF5EkTIUU2LcfWyCvq3S9y KwPNu67boLcLCBqrtZZNW+uVOJCk3AE= Message-ID: <34d95e25-be4a-406c-b486-0ad9e7c86838@ixit.cz> Date: Fri, 18 Sep 2026 00:10:00 +0200 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: [PATCH] serial: qcom-geni: keep registered console runtime active To: Konrad Dybcio , Greg Kroah-Hartman , Jiri Slaby , Praveen Talari Cc: linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, Konrad Dybcio References: <20260819-topic-geni_console_poweredoff-v1-1-7f7bb3aad8da@oss.qualcomm.com> Content-Language: en-US, cs-CZ From: David Heidelberg Autocrypt: addr=david@ixit.cz; keydata= xsFNBF5v1x4BEADS3EddwsNsvVAI1XF8uQKbdYPY/GhjaSLziwVnbwv5BGwqB1tfXoHnccoA 9kTgKAbiXG/CiZFhD6l4WCIskQDKzyQN3JhCUIxh16Xyw0lECI7iqoW9LmMoN1dNKcUmCO9g lZxQaOl+1bY/7ttd7DapLh9rmBXJ2lKiMEaIpUwb/Nw0d7Enp4Jy2TpkhPywIpUn8CoJCv3/ 61qbvI9y5utB/UhfMAUXsaAgwEJyGPAqHlC0YZjaTwOu+YQUE3AFzhCbksq95CwDz4U4gdls dmv9tkATfu2OmzERZQ6vJTehK0Pu4l5KmCAzYg42I9Dy4E6b17x6NncKbcByQFOXMtG0qVUk F1yeeOQUHwu+8t3ZDMBUhCkRL/juuoqLmyDWKMc0hKNNeZ9BNXgB8fXkRLWEUfgDXsFyEkKp NxUy5bDRlivf6XfExnikk5kj9l2gGlNQwqROti/46bfbmlmc/a2GM4k8ZyalHNEAdwtXYSpP 8JJmlbQ7hNTLkc3HQLRsIocN5th/ur7pPMz1Beyp0gbE9GcOceqmdZQB80vJ01XDyCAihf6l AMnzwpXZsjqIqH9r7T7tM6tVEVbPSwPt4eZYXSoJijEBC/43TBbmxDX+5+3txRaSCRQrG9dY k3mMGM3xJLCps2KnaqMcgUnvb1KdTgEFUZQaItw7HyRd6RppewARAQABzSBEYXZpZCBIZWlk ZWxiZXJnIDxkYXZpZEBpeGl0LmN6PsLBlAQTAQgAPgIbAwULCQgHAgYVCgkICwIEFgIDAQIe AQIXgBYhBNd6Cc/u3Cu9U6cEdGACP8TTSSByBQJl+KksBQkPDaAOAAoJEGACP8TTSSBy6IAQ AMqFqVi9LLxCEcUWBn82ssQGiVSDniKpFE/tp7lMXflwhjD5xoftoWOmMYkiWE86t5x5Fsp7 afALx7SEDz599F1K1bLnaga+budu55JEAYGudD2WwpLJ0kPzRhqBwGFIx8k6F+goZJzxPDsf loAtXQE62UvEKa4KRRcZmF0GGoRsgA7vE7OnV8LMeocdD3eb2CuXLzauHAfdvqF50IfPH/sE jbzROiAZU+WgrwU946aOzrN8jVU+Cy8XAccGAZxsmPBfhTY5f2VN1IqvfaRdkKKlmWVJWGw+ ycFpAEJKFRdfcc5PSjUJcALn5C+hxzL2hBpIZJdfdfStn+DWHXNgBeRDiZj1x6vvyaC43RAb VXvRzOQfG4EaMVMIOvBjBA/FtIpb1gtXA42ewhvPnd5RVCqD9YYUxsVpJ9d+XsAy7uib3BsV W2idAEsPtoqhVhq8bCUs/G4sC2DdyGZK8MRFDJqciJSUbqA+5z1ZCuE8UOPDpZKiW6H/OuOM zDcjh0lOzr4p+/1TSg1PbUh7fQ+nbMuiT044sC1lLtJK0+Zyn0GwhR82oNM4fldNsaHRW42w QGD35+eNo5Pvb3We5XRMlBdhFnj7Siggp4J8/PJ6MJvRyC+RIJPGtbdMB2/RxWunFLn87e5w UgwR9jPMHAstuTR1yR23c4SIYoQ2fzkrRzuazsFNBF5v1x4BEADnlrbta2WL87BlEOotZUh0 zXANMrNV15WxexsirLetfqbs0AGCaTRNj+uWlTUDJRXOVIwzmF76Us3I2796+Od2ocNpLheZ 7EIkq8budtLVd1c06qJ+GMraz51zfgSIazVInNMPk9T6fz0lembji5yEcNPNNBA4sHiFmXfo IhepHFOBApjS0CiOPqowYxSTPe/DLcJ/LDwWpTi37doKPhBwlHev1BwVCbrLEIFjY0MLM0aT jiBBlyLJaTqvE48gblonu2SGaNmGtkC3VoQUQFcVYDXtlL9CVbNo7BAt5gwPcNqEqkUL60Jh FtvVSKyQh6gn7HHsyMtgltjZ3NKjv8S3yQd7zxvCn79tCKwoeNevsvoMq/bzlKxc9QiKaRPO aDj3FtW7R/3XoKJBY8Hckyug6uc2qYWRpnuXc0as6S0wfek6gauExUttBKrtSbPPHiuTeNHt NsT4+dyvaJtQKPBTbPHkXpTO8e1+YAg7kPj3aKFToE/dakIh8iqUHLNxywDAamRVn8Ha67WO AEAA3iklJ49QQk2ZyS1RJ2Ul28ePFDZ3QSr9LoJiOBZv9XkbhXS164iRB7rBZk6ZRVgCz3V6 hhhjkipYvpJ/fpjXNsVL8jvel1mYNf0a46T4QQDQx4KQj0zXJbC2fFikAtu1AULktF4iEXEI rSjFoqhd4euZ+QARAQABwsF8BBgBCAAmAhsMFiEE13oJz+7cK71TpwR0YAI/xNNJIHIFAmX4 qVAFCQ8NoDIACgkQYAI/xNNJIHKN4A/+Ine2Ii7JiuGITjJkcV6pgKlfwYdEs4eFD1pTRb/K 5dprUz3QSLP41u9OJQ23HnESMvn31UENk9ffebNoW7WxZ/8cTQY0JY/cgTTrlNXtyAlGbR3/ 3Q/VBJptf04Er7I6TaKAmqWzdVeKTw33LljpkHp02vrbOdylb4JQG/SginLV9purGAFptYRO 8JNa2J4FAQtQTrfOUjulOWMxy7XRkqK3QqLcPW79/CFn7q1yxamPkpoXUJq9/fVjlhk7P+da NYQpe4WQQnktBY29SkFnvfIAwqIVU8ix5Oz8rghuCcAdR7lEJ7hCX9bR0EE05FOXdZy5FWL9 GHvFa/Opkq3DPmFl/0nt4HJqq1Nwrr+WR6d0414oo1n2hPEllge/6iD3ZYwptTvOFKEw/v0A yqOoYSiKX9F7Ko7QO+VnYeVDsDDevKic2T/4GDpcSVd9ipiKxCQvUAzKUH7RUpqDTa+rYurm zRKcgRumz2Tc1ouHj6qINlzEe3a5ldctIn/dvR1l2Ko7GBTG+VGp9U5NOAEkGpxHG9yg6eeY fFYnMme51H/HKiyUlFiE3yd5LSmv8Dhbf+vsI4x6BOOOq4Iyop/Exavj1owGxW0hpdUGcCl1 ovlwVPO/6l/XLAmSGwdnGqok5eGZQzSst0tj9RC9O0dXO1TZocOsf0tJ8dR2egX4kxM= In-Reply-To: <20260819-topic-geni_console_poweredoff-v1-1-7f7bb3aad8da@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 19/08/2026 18:46, Konrad Dybcio wrote: > From: Konrad Dybcio > > Commit aee1f94dab13 ("serial: qcom-geni: remove .pm callback, use > runtime PM in startup/shutdown") moved runtime PM references from the > serial-core PM callback to the port startup and shutdown callbacks. > > The serial core used to leave the console port powered after > registration, but after the callback was removed the temporary probe > reference is always released. Console writes are not tied to an open TTY > and can run from contexts which cannot resume the device, so a > runtime-suspended console can stall. This was observed on a Qualcomm > X1E80100 CRD device, as the boot console became flakey across boots. > > Acquire a runtime PM reference when the console is set up and release it > through the console exit callback. This keeps the device active only > while the console is registered and balances the reference when the > console is disabled or re-enabled through sysfs. > > Fixes: aee1f94dab13 ("serial: qcom-geni: remove .pm callback, use runtime PM in startup/shutdown") > Assisted-by: LLM > Signed-off-by: Konrad Dybcio > --- > drivers/tty/serial/qcom_geni_serial.c | 26 ++++++++++++++++++++++++-- > 1 file changed, 24 insertions(+), 2 deletions(-) > This also fixes a regression on sdm845: since v7.3-rc1 (or on next-20260820), OnePlus 6 and 6T crash into the Qualcomm crash dump mode on every s2idle suspend attempt (no kernel output, warm reset via PS_HOLD with the TZ download cookie set, no panic in ramoops). Tested-by: David Heidelberg # OnePlus 6T (sdm845) One thing this leaves open: with the console holding a single reference, pm_runtime_force_suspend() goes through pm_runtime_need_not_resume() and pm_runtime_force_resume() does not power the port back up, so uart_resume_port() programs the termios and resumes the console on a powered-down port; it only comes back through startup() if the tty was open. I'll send a patch on top for that. Thank you David