From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=205.220.180.131 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793720565; b=pseETM+dlG4B6sc5BVoTwq1ZLR8so4974Ld5xErSpKZuoMP037gcC5zAA5ey9cft0an+ ugVcOZ7kQMxFM/Atv9j/WctAOu0Ssx5kVqlYv5bgxTAw6t+VimZ/4rACPi5ytFV4gIAsx +dhBAyPwr1mECMC0gKpw8n08al1HsjmDSxV0OX9/iclVlcTYOWYvn5od5W3ECU+ctTPWy 1PMSbT0mM6mV9GOjPZ6bTzNAtXkNysstgl3AwdPgawt8EN1x7ET7vkWszu6I3QCd/T9vw mUHicVTHHFjOg/EFrdw6RkTvdRiZ2C2RZp04VCig6IWv3R8FQ3/xHNymlGU61qfuwVA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793720565; h=DMARC-Filter:Received:DKIM-Signature:Received:Received: DKIM-Signature:X-Google-DKIM-Signature:X-Forwarded-Encrypted: X-Gm-Message-State:X-Gm-Gg:X-Received:X-Received:Received:Message-ID: Date:MIME-Version:User-Agent:Subject:To:Cc:References: Content-Language:From:In-Reply-To:Content-Type: Content-Transfer-Encoding:X-Proofpoint-GUID:X-Proofpoint-Spam-Info: X-Authority-Analysis:X-Proofpoint-ORIG-GUID: X-Proofpoint-Spam-Details-Enc:X-Proofpoint-Virus-Version: X-Proofpoint-Spam-Details; bh=Qg5aVy+S20ZvI0/BdN6+9Xr4hUEBJxVpKOMywluWEWc=; b=pp53P3+NplW+XeSRluKHm8oK9HRNufr0eVEh51GmjFw8b+RWsdF35w/Zl59141AYtiV1 Nnfhl8kbFNSTqonyrLskuNzu35AN8Gq64N6Xy5CErLupyo0xsuwakguVy17vscEHL31ma ha2Ivj5+b1wxBt1427favdGU9OnZ0nuj/K+MaFPNf28QSWNsApFV/FHXjSoNmT5C5MBs2 3ucG9wghlvToi5E6k0EMXAnSnx6wzjwYXzNDCXkF+rWhAlN7UtnWiQSFPM4/8IJYMIFyR 4U6TcJqZBx/GtRTElIBJQRj7pzYF5A2KETfAois6rCmlbnC9V6X/nqvS3eHnfNRLQ+g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=oss.qualcomm.com; spf=pass smtp.mailfrom=oss.qualcomm.com; dkim=pass header.d=qualcomm.com header.i=@qualcomm.com header.a=rsa-sha256 header.s=qcppdkim1 header.b=eSFzNgd8; dkim=pass header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.a=rsa-sha256 header.s=google header.b=aYo67Wvw; arc=none smtp.remote-ip=205.220.180.131 Received: from mx0b-0031df01.pphosted.com (mx0b-0031df01.pphosted.com [205.220.180.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 80FB8606D822 for ; Tue, 3 Nov 2026 15:42:44 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 80FB8606D822 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oss.qualcomm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=qualcomm.com header.i=@qualcomm.com header.a=rsa-sha256 header.s=qcppdkim1 header.b=eSFzNgd8; dkim=pass (2048-bit key, unprotected) header.d=oss.qualcomm.com header.i=@oss.qualcomm.com header.a=rsa-sha256 header.s=google header.b=aYo67Wvw Received: from pps.filterd (m0279872.ppops.net [127.0.0.1]) by mx0a-0031df01.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 6A3E9xR22001388 for ; Tue, 3 Nov 2026 15:42:43 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qualcomm.com; h= cc:content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s=qcppdkim1; bh= Qg5aVy+S20ZvI0/BdN6+9Xr4hUEBJxVpKOMywluWEWc=; b=eSFzNgd8x3l1FanO GtqqbgWVVKkmVE01+RwG2kPpF5vEe1oOaxs8rw5fnzj1+WqU2s281JyMim73XwAh nn8KUV8hlyxdyyHAkbmThuamyDcBAnDbTkxn0THh3vajtZRasghaVFSKhNgvUJeq 4zXcM8/IwwwfGh6+OMzDDed5QxIeSc6cK5scq6pF+h7LpefGYnJKvl4bnsDCDjKg mv1BxE7wnmoZsqB6Wpi3l4gh2CwA/kV99+spaayhSQu/F8RFtFxFlIfBmr3iAu3o yJIcbF6hHeXl7/mlsO4HFUipExI68GlG60qDJ219Rcfqfn+tx/hxVMIl4tktT6Yi 1L9W8Q== Received: from mail-pj1-f72.google.com (mail-pj1-f72.google.com [209.85.216.72]) by mx0a-0031df01.pphosted.com (PPS) with ESMTPS id 4hq8u5jhmd-1 (version=TLSv1.3 cipher=TLS_AES_128_GCM_SHA256 bits=128 verify=NOT) for ; Tue, 03 Nov 2026 15:42:43 +0000 (GMT) Received: by mail-pj1-f72.google.com with SMTP id 98e67ed59e1d1-3ac76132001so2922338a91.0 for ; Tue, 03 Nov 2026 07:42:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oss.qualcomm.com; s=google; t=1793720562; x=1794325362; darn=vger.kernel.org; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Qg5aVy+S20ZvI0/BdN6+9Xr4hUEBJxVpKOMywluWEWc=; b=aYo67WvwnuWUkkcMgoKDBQ4fDgeUFEEgqdzpxixVizQBif0EXIROhVGzYjwFeJR55u eoT7FUUrj7P5dyYpVzdw39VWs1OcPY7qEEdtNe6JOvcxSM+P9VFZw3Z387tQZP5kpJn8 YYe7KqeIYqb1d2qcYkZffTr2+DoZbRBFAdP0OMYuh+lYMjHiLQQC169yG+hNCJy2Noln fTHfcNjL4lzhFXvQR4NNZsj1N0stIDHma5dVn9dNsYHU8mCpZZNDUsxbfGJSHiOLoVgI yPyGLe3IqcPE5MA6GbqpVXrRWtfTL7w2qjHRNkKwJ7pywI1OWOTkxvr/hGPT4N5dmFO2 eA0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793720562; x=1794325362; h=content-transfer-encoding:content-type:in-reply-to:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=Qg5aVy+S20ZvI0/BdN6+9Xr4hUEBJxVpKOMywluWEWc=; b=WsfZQCwRVoWgfh5pBNbmE8+WhHfjMnY93qjXDtpdv5ihuxkbORkRlTCDC28VRcgwIe j2yO4BJRWcjG11IpvwWi7vSmxDF607buMypnFagxotdGbQFgnB964dbe6wgYXaJt19+E XYI3USPEvVsPFdEIpp8O5h8ucmNNejRLJFkZLzVnNO8gS+oLq1+tJoggKGrtECfGOQ54 ssKnyBtbUnZhBcr7I5n2UMxM78RYopTYMR9Ghw2yFpwgNvTqXgCntcsMCHn75kPzxehZ 565lqM2VHB2WAEkaI5sdnNJaOjVQTl4uWw4+igtGmDIPHaMtu/i0kt4b0i5pLTPkG7U4 WCAg== X-Forwarded-Encrypted: i=1; AKwUvBxdMh90DQiBHRRHvFCkboQuiKv6z73TvB9k5Ax68/R7w94bbaYPZymtTJZ6LAQiKHQsJfNnPREydFuYTTA=@vger.kernel.org X-Gm-Message-State: APuU4Z+iKLEiklMA3o2JIUbsxRDYw6sC3+4WphIjNnY1H9G+rhHpMSTv 85+WohvC9ehhAH5fiwX8zrzZR8yN/OU3K8J5JTd0h/CCk2cD0tDOo1Dl55OVR933QGfhLS3Ve3i zA45zhYsF6ifSO+36CM2gVro1uIujbd8CvYhCBfs0X0tfCxFUaMEZVXQljdgL3zPuFTkplF5cSj s= X-Gm-Gg: AYBFou3Mwsf/ezgoUzlrY714HX2+ThC1baWWx9gzbYJzQhcX9RJHSc1hp4QXDuTYTns aHDUHAUPbDCCteWYEZ5xSJzybE+Eg3CfJOiOHThM8jUVJiX+RIZSRwgfeLH8YmK4qDDKe0Md8Pl HObU93LrzXBVj4A7YiA9wIwatz0aOa0fAcxzhAw5/1AwOnT76jIq1g5ZXzI784E474bwVCtOlxG OxUIRdjnx90JXTPfAeGi1uulqNydpRhCdgOOteZRYb0ChYYFM/YRBWWbtZt6cq2bsLLIg1t6WrB +Eefu3OjGy3SmdNNBo50MYVVd/G2cltziohCelI+pDczot9bMnsXtyBRVnskUQaxsEoX8XUcFBl x/xfJesrcR3UIDkw6whJcVuBdlTjHmfmQQDotbEk+ZZv+QaqNgNH/6LRryDAIZ2coZA6DugaapL o= X-Received: by 2002:a17:90b:5807:b0:3ab:be66:ddbf with SMTP id 98e67ed59e1d1-3ae8981dd4dmr10490386a91.54.1793720562128; Tue, 03 Nov 2026 07:42:42 -0800 (PST) X-Received: by 2002:a17:90b:5807:b0:3ab:be66:ddbf with SMTP id 98e67ed59e1d1-3ae8981dd4dmr10490349a91.54.1793720561587; Tue, 03 Nov 2026 07:42:41 -0800 (PST) Received: from [10.206.96.127] ([202.46.23.25]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3b07c7dea24sm4786035a91.5.2026.11.03.07.42.36 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Nov 2026 07:42:40 -0800 (PST) Message-ID: <719999ca-28b7-4c71-8d85-87c3faaa121c@oss.qualcomm.com> Date: Tue, 3 Nov 2026 21:12:34 +0530 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] drm/msm: restore GEM-related IOCTLs for KMS devices To: Dmitry Baryshkov , Rob Clark Cc: Dmitry Baryshkov , Abhinav Kumar , Jessica Zhang , Sean Paul , Marijn Suijten , David Airlie , Simona Vetter , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org References: <20260304-msm-restore-ioctls-v1-1-b28f9231fcd2@oss.qualcomm.com> Content-Language: en-US From: Mahadevan P In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Proofpoint-GUID: sqIA3o400bAJc_xmbFiKZuND3_Eb6TQN X-Proofpoint-Spam-Info: AW1haW4tMjYxMTAzMDA2MiBTYWx0ZWRfXy2PwMmqUPJXW 2eTH4pA7Ruf09fgFPfcGU0s1BcfysdmstawKvWj+xqKrOcvsAyaLdejoIiPfB2DHViM4e1BRg96 HafiX82VyP4FpPBVY4eQT45KlMZpdZw= X-Authority-Analysis: v=2.4 cv=RZ0FmFtv c=1 sm=1 tr=0 ts=6aea00f3 cx=c_pps a=RP+M6JBNLl+fLTcSJhASfg==:117 a=ZePRamnt/+rB5gQjfz0u9A==:17 a=IkcTkHD0fZMA:10 a=zJRp6_cAMcgA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=yx91gb_oNiZeI1HMLzn7:22 a=EUspDBNiAAAA:8 a=G6p25mnS-FJF_-mfOFUA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=iS9zxrgQBfv6-_F4QbHw:22 X-Proofpoint-ORIG-GUID: sqIA3o400bAJc_xmbFiKZuND3_Eb6TQN X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMTAzMDA2MiBTYWx0ZWRfX9e4BTDMWbLKl 6obzeqlGhVsfeVZWXBpx73njUqZVRBnHv8Gd+K6hW25cTTVy1H8eFstdB9OXXFGHG/fAwRrp40Y q/EwvEzgvvrT8ajU0x4w9lPIH8Rytx4pAQ+FGOFtBwjgtNsoDGyhhGY4P+/PVol5YpVVqYuaE+A zmpKr9+xToN4/bYERozC5RCBtNaFKjg4tnLsvR/p2/ih3EElhMVIOvz5hdPbJxjlAYB96GTn4Tk ou7d+jODEVinAm753N/Xt365kbTm+7M7qxPvZHMytwg2Iohfyv2xVM7oBH1j7MhHccKAinoQmiG /MU6OhKDFQK82J6ca4mXjdYE56Njauu1wZ8/0bUFocAYcY62Q8CxLpg+yYDLiGolVtdJOSFMCWz Z7751wBB8A4N/3GgkMMvy/8UV9jmiw7AOcSAIuAklRLRwnx10E/aGdyG16u5A7Awml8CWEBUWKd Z+VdcPHzYNFKI1Ndv9Q== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-11-03_03,2026-11-03_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 bulkscore=0 impostorscore=0 phishscore=0 suspectscore=0 adultscore=0 lowpriorityscore=0 spamscore=0 malwarescore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610300000 definitions=main-2611030062 On 3/5/2026 6:14 AM, Dmitry Baryshkov wrote: > On Wed, Mar 04, 2026 at 07:57:34AM -0800, Rob Clark wrote: >> On Wed, Mar 4, 2026 at 5:34 AM Dmitry Baryshkov >> wrote: >>> The MSM GBM backend uses MSM_GEM_NEW to allocate GEM buffers from the >>> KMS driver, imports them into the GPU driver (msm or kgsl) and then >>> uses them for rendering / blending. Commit 98f11fd1cf92 ("drm/msm: Take >>> the ioctls away from the KMS-only driver") dropped all IOCTLs from the >>> MSM KMS devices, pointing out the need to use dumb buffers, however dumb >>> buffers should not be used by the GPU for rendering. Restore GEM-related >>> IOCTLs for the KMS devices. >> We shouldn't be exposing DRIVER_RENDER on KMS-only nodes. If msm gbm >> is allocating from a primary node, that is problematic, since there is >> no guarantee that anything but the compositor has access to the >> primary node. > We are not exposing DRIVER_RENDER for KMS-only nodes. I'll check with > the correponding colleagues, what exactly is their use case, if the > allocation is happening in the compositor or in the app. In the latter > case, I agree, the buffers should be allocated from the GPU. Hi Rob, In combination of msm-kms with kgsl, wayland clients allocate their own dma-bufs (typically through EGL/GLES on KGSL) and pass the fd to Weston, which imports them. Weston is therefore not allocating client buffers. GBM is mainly used for Weston-owned allocations such as render targets, composition buffers, and scanout/framebuffers. It can also be used by applications that allocate through  EGL (GBM-based path). One additional consideration is that KGSL is not a DRM driver and does not expose a DRM render node. Since |gbm_create_device()| operates on DRM devices and relies on DRM interfaces such as |drmGetVersion()|, a KGSL device cannot be used as a GBM device. As a result, the MSM DRM/KMS node remains the natural GBM allocation point in this configuration. Thus we need to add render support in msm-kms driver. Thanks, Mahadevan >> BR, >> -R >> >>> Fixes: 98f11fd1cf92 ("drm/msm: Take the ioctls away from the KMS-only driver") >>> Signed-off-by: Dmitry Baryshkov >>> --- >>> Note, here I assume that dumb buffers generally should not be used for >>> rendering. That doesn't seem to be complete truth as Mesa kmsro on MSM >>> devices uses DRM_IOCTL_MODE_CREATE_DUMB to create buffers for resources. >>> --- >>> drivers/gpu/drm/msm/msm_drv.c | 10 ++++++++++ >>> 1 file changed, 10 insertions(+) >>> >>> diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c >>> index ed2a61c66ac9..f82c9a36a166 100644 >>> --- a/drivers/gpu/drm/msm/msm_drv.c >>> +++ b/drivers/gpu/drm/msm/msm_drv.c >>> @@ -799,6 +799,14 @@ static const struct drm_ioctl_desc msm_ioctls[] = { >>> DRM_IOCTL_DEF_DRV(MSM_VM_BIND, msm_ioctl_vm_bind, DRM_RENDER_ALLOW), >>> }; >>> >>> +static const struct drm_ioctl_desc msm_kms_ioctls[] = { >>> + DRM_IOCTL_DEF_DRV(MSM_GEM_NEW, msm_ioctl_gem_new, DRM_RENDER_ALLOW), >>> + DRM_IOCTL_DEF_DRV(MSM_GEM_INFO, msm_ioctl_gem_info, DRM_RENDER_ALLOW), >>> + DRM_IOCTL_DEF_DRV(MSM_GEM_CPU_PREP, msm_ioctl_gem_cpu_prep, DRM_RENDER_ALLOW), >>> + DRM_IOCTL_DEF_DRV(MSM_GEM_CPU_FINI, msm_ioctl_gem_cpu_fini, DRM_RENDER_ALLOW), >>> + DRM_IOCTL_DEF_DRV(MSM_GEM_MADVISE, msm_ioctl_gem_madvise, DRM_RENDER_ALLOW), >>> +}; >>> + >>> static void msm_show_fdinfo(struct drm_printer *p, struct drm_file *file) >>> { >>> struct drm_device *dev = file->minor->dev; >>> @@ -868,6 +876,8 @@ static const struct drm_driver msm_kms_driver = { >>> #endif >>> MSM_FBDEV_DRIVER_OPS, >>> .show_fdinfo = msm_show_fdinfo, >>> + .ioctls = msm_kms_ioctls, >>> + .num_ioctls = ARRAY_SIZE(msm_kms_ioctls), >>> .fops = &fops, >>> .name = "msm-kms", >>> .desc = "MSM Snapdragon DRM", >>> >>> --- >>> base-commit: ac47870fd795549f03d57e0879fc730c79119f4b >>> change-id: 20260304-msm-restore-ioctls-2a1792311a09 >>> >>> Best regards, >>> -- >>> With best wishes >>> Dmitry >>>