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[165.204.72.6]) by smtp.gmail.com with ESMTPSA id n10-20020adfe78a000000b0031aca6cc69csm17618765wrm.2.2023.09.05.06.28.15 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 05 Sep 2023 06:28:16 -0700 (PDT) Message-ID: Date: Tue, 5 Sep 2023 15:28:14 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.13.0 Subject: Re: [RFC, drm-misc-next v4 0/9] PCI/VGA: Allowing the user to select the primary video adapter at boot time Content-Language: en-US To: Jani Nikula , Sui Jingfeng , Bjorn Helgaas Cc: Sui Jingfeng , nouveau@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-pci@vger.kernel.org References: <20230904195724.633404-1-sui.jingfeng@linux.dev> <874jk8j45s.fsf@intel.com> From: =?UTF-8?Q?Christian_K=c3=b6nig?= In-Reply-To: <874jk8j45s.fsf@intel.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Am 05.09.23 um 12:38 schrieb Jani Nikula: > On Tue, 05 Sep 2023, Sui Jingfeng wrote: >> From: Sui Jingfeng >> >> On a machine with multiple GPUs, a Linux user has no control over which >> one is primary at boot time. This series tries to solve above mentioned >> problem by introduced the ->be_primary() function stub. The specific >> device drivers can provide an implementation to hook up with this stub by >> calling the vga_client_register() function. >> >> Once the driver bound the device successfully, VGAARB will call back to >> the device driver. To query if the device drivers want to be primary or >> not. Device drivers can just pass NULL if have no such needs. >> >> Please note that: >> >> 1) The ARM64, Loongarch, Mips servers have a lot PCIe slot, and I would >> like to mount at least three video cards. Well, you rarely find a board which can actually handle a single one :) >> >> 2) Typically, those non-86 machines don't have a good UEFI firmware >> support, which doesn't support select primary GPU as firmware stage. >> Even on x86, there are old UEFI firmwares which already made undesired >> decision for you. >> >> 3) This series is attempt to solve the remain problems at the driver level, >> while another series[1] of me is target to solve the majority of the >> problems at device level. >> >> Tested (limited) on x86 with four video card mounted, Intel UHD Graphics >> 630 is the default boot VGA, successfully override by ast2400 with >> ast.modeset=10 append at the kernel cmd line. > The value 10 is incredibly arbitrary, and multiplied as a magic number > all over the place. +1 > >> $ lspci | grep VGA >> >> 00:02.0 VGA compatible controller: Intel Corporation CoffeeLake-S GT2 [UHD Graphics 630] >> 01:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Caicos XTX [Radeon HD 8490 / R5 235X OEM] >> 04:00.0 VGA compatible controller: ASPEED Technology, Inc. ASPEED Graphics Family (rev 30) >> 05:00.0 VGA compatible controller: NVIDIA Corporation GK208B [GeForce GT 720] (rev a1) > In this example, all of the GPUs are driven by different drivers. What > good does a module parameter do if you have multiple GPUs of the same > model, all driven by the same driver module? Completely agree. Question is what is the benefit for the end user to actually specify this? If you want the initial console on a different device than implement a kernel options for vgaarb and *not* the drivers. Regards, Christian. > > BR, > Jani. > >> $ sudo dmesg | grep vgaarb >> >> pci 0000:00:02.0: vgaarb: setting as boot VGA device >> pci 0000:00:02.0: vgaarb: VGA device added: decodes=io+mem,owns=io+mem,locks=none >> pci 0000:01:00.0: vgaarb: VGA device added: decodes=io+mem,owns=none,locks=none >> pci 0000:04:00.0: vgaarb: VGA device added: decodes=io+mem,owns=none,locks=none >> pci 0000:05:00.0: vgaarb: VGA device added: decodes=io+mem,owns=none,locks=none >> vgaarb: loaded >> ast 0000:04:00.0: vgaarb: Override as primary by driver >> i915 0000:00:02.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=none:owns=io+mem >> radeon 0000:01:00.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=none:owns=none >> ast 0000:04:00.0: vgaarb: changed VGA decodes: olddecodes=io+mem,decodes=none:owns=none >> >> v2: >> * Add a simple implemment for drm/i915 and drm/ast >> * Pick up all tags (Mario) >> v3: >> * Fix a mistake for drm/i915 implement >> * Fix patch can not be applied problem because of merge conflect. >> v4: >> * Focus on solve the real problem. >> >> v1,v2 at https://patchwork.freedesktop.org/series/120059/ >> v3 at https://patchwork.freedesktop.org/series/120562/ >> >> [1] https://patchwork.freedesktop.org/series/122845/ >> >> Sui Jingfeng (9): >> PCI/VGA: Allowing the user to select the primary video adapter at boot >> time >> drm/nouveau: Implement .be_primary() callback >> drm/radeon: Implement .be_primary() callback >> drm/amdgpu: Implement .be_primary() callback >> drm/i915: Implement .be_primary() callback >> drm/loongson: Implement .be_primary() callback >> drm/ast: Register as a VGA client by calling vga_client_register() >> drm/hibmc: Register as a VGA client by calling vga_client_register() >> drm/gma500: Register as a VGA client by calling vga_client_register() >> >> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 11 +++- >> drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c | 13 ++++- >> drivers/gpu/drm/ast/ast_drv.c | 31 ++++++++++ >> drivers/gpu/drm/gma500/psb_drv.c | 57 ++++++++++++++++++- >> .../gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 15 +++++ >> drivers/gpu/drm/i915/display/intel_vga.c | 15 ++++- >> drivers/gpu/drm/loongson/loongson_module.c | 2 +- >> drivers/gpu/drm/loongson/loongson_module.h | 1 + >> drivers/gpu/drm/loongson/lsdc_drv.c | 10 +++- >> drivers/gpu/drm/nouveau/nouveau_vga.c | 11 +++- >> drivers/gpu/drm/radeon/radeon_device.c | 10 +++- >> drivers/pci/vgaarb.c | 43 ++++++++++++-- >> drivers/vfio/pci/vfio_pci_core.c | 2 +- >> include/linux/vgaarb.h | 8 ++- >> 14 files changed, 210 insertions(+), 19 deletions(-)