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dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from SJ2PR12MB9161.namprd12.prod.outlook.com (2603:10b6:a03:566::20) by IA4PR12MB721289.namprd12.prod.outlook.com (2603:10b6:207:10b::15) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.592.12; Mon, 9 Nov 2026 03:27:33 +0000 Received: from SJ2PR12MB9161.namprd12.prod.outlook.com ([fe80::d9d1:8c49:a703:b017]) by SJ2PR12MB9161.namprd12.prod.outlook.com ([fe80::d9d1:8c49:a703:b017%5]) with mapi id 15.21.0592.010; Mon, 9 Nov 2026 03:27:32 +0000 From: Mikko Perttunen To: thierry.reding@kernel.org, linux-staging@lists.linux.dev Cc: DelaySystem , dri-devel@lists.freedesktop.org, luca.ceresoli@bootlin.com, gregkh@linuxfoundation.org, mchehab@kernel.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, clamor95@gmail.com, jonathanh@nvidia.com, linux-tegra@vger.kernel.org, skomatineni@nvidia.com, linux-media@vger.kernel.org, DelaySystem@tubot.lat Subject: Re: [PATCH RFC 0/2] Uninterruptible host1x syncpoint wait for Tegra video capture Date: Mon, 09 Nov 2026 12:27:29 +0900 Message-ID: In-Reply-To: <20261107-batch1-b1-host1x-wait-v1-0-8c8198adf600@tubot.lat> References: <20261107-batch1-b1-host1x-wait-v1-0-8c8198adf600@tubot.lat> Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; 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At high > resolutions and framerates these spurious failures are common, so the > driver wraps both waits in do/while retry loops, with a TODO asking > for an uninterruptible variant of the wait. >=20 > This series proposes one: patch 1 refactors host1x_syncpt_wait() so > the interruptible behavior is preserved exactly for existing callers > (including two DRM ioctls that are userspace ABI and must stay > interruptible) and adds host1x_syncpt_wait_uninterruptible() for > in-kernel users. Patch 2 converts the Tegra20 capture waits and drops > the retry loops and the TODO. >=20 > This is sent as an RFC because the API shape and the scope need > agreement before a final series: >=20 > 1. Is a separate _uninterruptible() variant the shape host1x wants, > or would the maintainers prefer something else (for example an > internal helper with a flag, or a different name)? > 2. Tegra210's two waits (tegra210.c) have no retry loop: a spurious > -ERESTARTSYS currently fails the buffer. Should they convert to > the uninterruptible wait as well, or is failing on signal > intentional there? > 3. drivers/crypto/tegra/tegra-se-main.c also waits with > MAX_SCHEDULE_TIMEOUT; left out of scope here, but flagging in > case its maintainer wants the same treatment. >=20 > drivers/staging/media/tegra-video with VIDEO_TEGRA=3Dm, zero warnings). > The tegra20.c change itself has no compile coverage here: that object > builds only for 32-bit ARM (ARCH_TEGRA_2x_SOC/_3x_SOC) and no ARM > toolchain is available, and there is no Tegra hardware for runtime > testing. Hardware testing help is needed before any final series. nak >=20 > Testing: compile-tested only (arm64: drivers/gpu/host1x and > --- > DelaySystem (2): > gpu: host1x: add uninterruptible syncpoint wait variant > staging: media: tegra-video: uninterruptible syncpt wait for tegra2= 0 >=20 > drivers/gpu/host1x/syncpt.c | 46 ++++++++++++++++++++++-= ------ > drivers/staging/media/tegra-video/tegra20.c | 37 +++++++---------------- > include/linux/host1x.h | 2 ++ > 3 files changed, 48 insertions(+), 37 deletions(-) > --- > base-commit: fa4ad798f6f681031775266044ba1b0cf3c670bd > change-id: 20261107-batch1-b1-host1x-wait-3cb3b92e9199 >=20 > Best regards, > -- =20 > DelaySystem >=20 >=20 >=20