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b=JB8OjMCtCzJ1YInn4tNfeR0v0PbEPGZGOGVlzbzrit48JNQTeiTdt+9vYx4sh+wmawS/6N CETWdosaxauFkwlusUa9edkiZgRA6Ds9BO18Zl/y2+e36l0G7BDMOGrYrL+wG0xPiz6kvh NdCEI9zw1kowE2dr151TWTPB2obKNZHjLQsEqqALDY4IBajPhsJh8KGxAekJtz2SszH+ra P9Cv91kFMMvIoKx0qeykfMlaoVZSoamphKkqkcGwSiatDie1PU6n+6jTGQN1TvfxkqrFaX 2IbDUk+L0Evph8E7rEmZiInCnG2QeentPxoE4AE7iwU5AZ8q75g5aRQAGmX7Ew== From: Louis Chauvet Date: Tue, 25 Feb 2025 16:46:22 +0100 Subject: [PATCH] drm/vkms: Add "hardware limitation" emulation TODO Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20250225-vkms-update-todo-v1-1-afb1e6f7d714@bootlin.com> X-B4-Tracking: v=1; b=H4sIAM3lvWcC/zWMQQrCMBBFr1Jm7WAaGpVeRbpIk1EHSVIzaSmU3 t1gcfffh/c2EMpMAn2zQaaFhVOs0J4acC8bn4TsK4NW2iitDS7vIDhP3hbCknxCo66q1d1ldP4 GVZsyPXj9Je/DwZk+cy2X44TRCqFLIXDpG58DBhZ3/g+MtBYY9v0LdOQsTJwAAAA= X-Change-ID: 20250225-vkms-update-todo-50701246bcd8 To: Haneen Mohammed , Simona Vetter , Melissa Wen , David Airlie , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , Jonathan Corbet Cc: thomas.petazzoni@bootlin.com, dri-devel@lists.freedesktop.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Louis Chauvet X-Mailer: b4 0.15-dev X-Developer-Signature: v=1; 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a=openpgp; fpr=8B7104AE9A272D6693F527F2EC1883F55E0B40A5 X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdekvddutdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhephfffufggtgfgkffvvefosehtjeertdertdejnecuhfhrohhmpefnohhuihhsucevhhgruhhvvghtuceolhhouhhishdrtghhrghuvhgvthessghoohhtlhhinhdrtghomheqnecuggftrfgrthhtvghrnhepueetjeeggeffvdegkeetudekjeevkeehheduledtgeejhfduvdeuleehleffgefgnecukfhppeeltddrkeelrdduieefrdduvdejnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepledtrdekledrudeifedruddvjedphhgvlhhopegludejvddrudekrddtrddungdpmhgrihhlfhhrohhmpehlohhuihhsrdgthhgruhhvvghtsegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopedufedprhgtphhtthhopehmrhhiphgrrhgusehkvghrnhgvlhdrohhrghdprhgtphhtthhopegrihhrlhhivggusehgmhgrihhlrdgtohhmpdhrtghpthhtohephhgrmhhohhgrmhhmvggurdhsrgesghhmrghilhdrtghomhdprhgtphhtthhopegtohhrsggvtheslhifnhdrnhgvthdprhgtphhtthhopehlihhnuhigqdguohgtsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhouhhis hdrtghhrghuvhgvthessghoohhtlhhinhdrtghomhdprhgtphhtthhopegurhhiqdguvghvvghlsehlihhsthhsrdhfrhgvvgguvghskhhtohhprdhorhhgpdhrtghpthhtohepshhimhhonhgrsehffhiflhhlrdgthh X-GND-Sasl: louis.chauvet@bootlin.com Add the hardware limitation todo. Signed-off-by: Louis Chauvet Reviewed-by: Maxime Ripard --- Documentation/gpu/vkms.rst | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst index ba04ac7c2167..d5bc602547e7 100644 --- a/Documentation/gpu/vkms.rst +++ b/Documentation/gpu/vkms.rst @@ -147,6 +147,15 @@ module. Use/Test-cases: - Change output configuration: Plug/unplug screens, change EDID, allow cha= nging the refresh rate. =20 +- Emulating Hardware Limitations with eBPF for MST and Atomic Checks + Hardware limitations can often prevent valid DRM configurations during + atomic checks. Examples of such limitations include bandwidth constraint= s in + MST and limited clock signals for multiple CRTCs. + These limitations are dynamic and require extensive checks, making them + difficult to describe statically. To address this, we propose creating an + eBPF interface for atomic checks. This interface will allow userspace ap= plications + to simulate and enforce custom hardware limitations. + The currently proposed solution is to expose vkms configuration through configfs. All existing module options should be supported through configfs too. --- base-commit: acf3256160bdabcb5c07032f3bf6eb5a21f5b95f change-id: 20250225-vkms-update-todo-50701246bcd8 Best regards, --=20 Louis Chauvet