From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 24903CA5FA5 for ; Tue, 29 Sep 2026 19:54:04 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6E04310E1EA; Tue, 29 Sep 2026 19:54:03 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="AxGSA/qI"; dkim-atps=neutral Received: from mail-wm2-f13.google.com (mail-wm2-f13.google.com [74.125.225.141]) by gabe.freedesktop.org (Postfix) with ESMTPS id 02A0110E1EA for ; Tue, 29 Sep 2026 19:54:03 +0000 (UTC) Received: by mail-wm2-f13.google.com with SMTP id 5b1f17b1804b1-49e8185e037so26206125e9.3 for ; Tue, 29 Sep 2026 12:54:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1790711641; x=1791316441; darn=lists.freedesktop.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:from:to:cc:subject :date:message-id:reply-to:content-type; bh=u27k5NmvBzDFGlc9tKb68XrZeYB1FzHqqK5+lL8nqVA=; b=AxGSA/qIrsfJkH0mDzprVDVVysl89H/Ds0TPllcO/HFekCcT+mGXllSlEy1Bl8TsFf uFAl1vtUa/e0XYclU/7EKyVbqGAeTI/KRQwMRH3yK+abKkaIOq+U9g/ge2ufwoRvD3Xy sMls+ED9OmA+nNA2sHXDz4KE9/PogUh1BKHjMfjS+HRvix0vXwlfJKC9gdumS21xagoy lr/LDklWKPjCVXZ72L0SC5Rg9HqGPsNtDSUg5B0yg+VCzM1HUbq/les/nj7IerqvtVSC Iu1Rzf4xRPUzslcvCTZ/HZSiWkg4u4JldVbD1OZl6QCZdvBUlDxBrZi6hotCuS7huqwo xQEg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790711641; x=1791316441; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=u27k5NmvBzDFGlc9tKb68XrZeYB1FzHqqK5+lL8nqVA=; b=AthWDJw6tNykqUI4APQOnpOHYc5pqi6gGAgU+f3O8VDaOJzxXenUslZphBMIm1EBgF 1/3ZTE67rHAyw3nB3Dk1CES1UihYTtb1P6phQxuSN4FcOm+tvLdSTY6vvizUIdLdxMqr xtK4OMXU/gYNvmlF77eAWGMcML8vGk4KLn9wzEyKMdzWe+/0kvQ5EqimfQ+2WkB1DqIc ZNLKmRYX1+n6QHVJz+9jJgFVDfJc6M9RNL8t5ObM45eMGKh/c60fPSE5X78/GRdIkxof NbRhn84pF6g7CqmuXcZI3/8pwKN2u8RSxwhT4fyFWwIJ/xae2QNi7sqC/OUj41bFgKh6 HmOA== X-Forwarded-Encrypted: i=1; AKwUvBzMInu4V1FfapNjLVyrIMpR2mz/M/2EjTk4KEulfa3ddffeb9DnVv0VbZPa/BosUaDA+ogd2GkJ61w=@lists.freedesktop.org X-Gm-Message-State: AFuF++lhUzZUIjL/B9406IehM66CFtUgrA9HR9Dy00S0SwxOw12EqyIi 1rpG7ZLhioy81IlLHiuoK4uh6x/mNZnvzysy7cT/h+BUhxTpflaM2tpU/YGtYbhp X-Gm-Gg: AYBFou1PlGP+xEriavzVFeVlyZG4msPGFb0cnbtxPZo5OxEh8HdlOeD74X0lNQ1PLGD q/noVkLBqxpNl/CX/VC9eIwsTxr87VKIt+xwHe5d0UzI3Gp7gQEJL4+OfYV+DiWnMy4kKejHhz+ kMyMEDye41IIm9mS52TmBMlpAPkShskhF+M0RKTJy0zjOjkvY7MJ5RQzYY9oWGV4m0CaHO7jIab SjvspB3f1auQkGWQLCqD2T3+hiwf7IVZVhSIvLHVATjBOoQpmo4R0GgvMnydUud+RfhZCXj4j3u /w4x3ALe8Vuv8b9o/S4LPMp1+8JO/53allUXx279140Wc3ahLX2wfZl1q/T6AFa6HXz1PAuLCsy NZo++DWP9klve9XWhT1vN4WfnStNCnfLHipRNPjgZRrepzWrTNWkUFKwYru1fo7rhu8rDweurfB 59NYwtFTEQtf4wZmcd2CLuunePXORSiBvmAyY8z0WM16boVTdV0reToewtWY4RplT3zFJeEopr9 5CEfNM6zUIpQlvi40d+BQiJI3lbL7FID1+dAJR8vGz6uVFUEqpAwUttx/DaaV03VAlz39iRHdPO 6o4INhs3XaJ4QG/1l2ipulRr9bn3ZUp25zFnJN9RlQjK1aXKlInGCtJ9PbMxJYVEfUC3agsK4CB 7qd/W2g== X-Received: by 2002:a05:600c:3ba3:b0:49c:fc6c:be03 with SMTP id 5b1f17b1804b1-4a015155f74mr2815545e9.26.1790711641143; Tue, 29 Sep 2026 12:54:01 -0700 (PDT) Received: from MBP-von-Karl (dynamic-2a02-3100-9c32-f801-9d9d-c89f-9fb1-4ec2.310.pool.telefonica.de. [2a02:3100:9c32:f801:9d9d:c89f:9fb1:4ec2]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a015019e5asm8566915e9.2.2026.09.29.12.53.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Sep 2026 12:54:00 -0700 (PDT) Date: Tue, 29 Sep 2026 21:53:59 +0200 From: Karl Mehltretter To: Jason Gunthorpe , g@mbp-von-karl Cc: sashiko-bot@kernel.org, Gerd Hoffmann , Vivek Kasireddy , Sumit Semwal , Christian =?utf-8?B?S8O2bmln?= , dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] udmabuf: respect the device's maximum segment sizeg Message-ID: References: <20260929054835.94118-1-kmehltretter@gmail.com> <20260929060028.371041F00893@smtp.kernel.org> <20260929065601.99518-1-kmehltretter@gmail.com> <20260929120317.GH1616761@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260929120317.GH1616761@nvidia.com> X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Tue, Sep 29, 2026 at 09:03:17AM +0100, Jason Gunthorpe wrote: > On Tue, Sep 29, 2026 at 08:56:01AM +0200, Karl Mehltretter wrote: > > Right, the misc device has no dma_parms, so it gets the 64K default and > > sync fails with 256K pages > > I would ignore this, it seems fictional to me, and if someone really > needs to support this rediculous combination it should be done inside > sg_alloc_table_from_pages_segment(:) > Fair enough, Sashiko got me there. Looking around, 256K pages seem to be barely supported today: they were already disabled for 47x, and I couldn't get userspace running on a 256K-page 44x kernel in QEMU. I'll leave v2 as is. Thanks for the review. Karl