Lines Matching +full:mode +full:- +full:recovery
9 addition, drivers export device-specific interfaces for use by userspace
10 drivers & device-aware applications through ioctls and sysfs files.
16 Cover generic ioctls and sysfs layout here. We only need high-level
22 .. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
31 .. kernel-doc:: drivers/gpu/drm/drm_auth.c
34 .. kernel-doc:: drivers/gpu/drm/drm_auth.c
37 .. kernel-doc:: include/drm/drm_auth.h
46 .. kernel-doc:: drivers/gpu/drm/drm_lease.c
49 Open-Source Userspace Requirements
57 open-sourced userspace patches, and those patches must be reviewed and ready for
75 - The Linux kernel's "no regression" policy holds in practice only for
76 open-source userspace of the DRM subsystem. DRM developers are perfectly fine
77 if closed-source blob drivers in userspace use the same uAPI as the open
82 - Any new userspace interface must have an open-source implementation as
85 The other reason for requiring open-source userspace is uAPI review. Since the
88 both sides. Making sure that the interface indeed covers the use-case fully
91 - The open-source userspace must not be a toy/test application, but the real
96 - The userspace side must be fully reviewed and tested to the standards of that
99 job done. The userspace-side reviewer should also provide an Acked-by on the
103 - The userspace patches must be against the canonical upstream, not some vendor
107 - The kernel patch can only be merged after all the above requirements are met,
108 but it **must** be merged to either drm-next or drm-misc-next **before** the
118 for the same thing co-existing. If we add a few more complete mistakes into the
126 DRM core provides multiple character-devices for user-space to use.
127 Depending on which device is opened, user-space can perform a different
139 authenticate to a DRM-Master prior to getting GPU access. To avoid this
143 Only non-global rendering commands are allowed. If a driver supports
150 per device. No ioctls except PRIME-related ioctls will be allowed on
152 complete list of driver-independent ioctls that can be used on render
154 nodes are designed to avoid the buffer-leaks, which occur if clients
157 driver-dependent render-only ioctls as DRM_RENDER_ALLOW so render
161 With render nodes, user-space can now control access to the render node
162 via basic file-system access-modes. A running graphics server which
170 DRM-Master concept. There is no reason to associate render clients with
171 a DRM-Master as they are independent of any graphics server. Besides,
175 visible to user-space and accessible beyond open-file boundaries, they
178 Device Hot-Unplug
187 user is able to hot-unplug this kind of devices while they are being
189 damage from hot-unplugging a DRM device needs to be limited as much as
204 (or driver-specific ioctls returning driver-specific things), or open()
222 -------------------------
224 - KMS connectors must change their status to disconnected.
226 - Legacy modesets and pageflips, and atomic commits, both real and
230 - Pending non-blocking KMS operations deliver the DRM events userspace
233 - open() on a device node whose underlying device has disappeared will
236 - Attempting to create a DRM lease on a disappeared DRM device will
240 Requirements for Render and Cross-Device UAPI
241 ---------------------------------------------
243 - All GPU jobs that can no longer run must have their fences
244 force-signalled to avoid inflicting hangs on userspace.
247 - Some userspace APIs already define what should happen when the device
251 driver-specific ioctls and handling those in userspace drivers, or
254 - dmabuf which point to memory that has disappeared will either fail to
259 - Attempting to import a dmabuf to a disappeared device will either fail
263 - open() on a device node whose underlying device has disappeared will
270 ----------------------------
277 dmabuf which might be mapped to other devices (cross-device dmabuf
304 Kernel Mode Driver
305 ------------------
329 User Mode Driver
330 ----------------
340 ----------
347 userspace that doesn't support robust interfaces (like a non-robust
370 --------------------------
375 information about the reset and send device wedged event with ``none`` recovery
389 re-enumerating the full bus, on which the underlying physical device is sitting)
399 drivers to decide when they see the need for device recovery and how they want
403 --------------------
405 The driver, before opting for recovery, needs to make sure that the 'wedged'
412 device must be kept in 'wedged' state until the recovery is performed. New
418 Recovery section in Device Wedging
419 --------
421 Current implementation defines three recovery methods, out of which, drivers
424 more side-effects. If driver is unsure about recovery or method is unknown
429 Userspace consumers can parse this event and attempt recovery as per the
433 Recovery method Consumer expectations
437 bus-reset unbind + bus reset/re-enumeration + bind
443 using device specific methods like reset. No explicit recovery is expected from
450 ----------------------
453 resources are not in use by any process before attempting recovery. With IOCTLs
456 device of all user context beforehand and set the stage for a clean recovery.
459 -------
463 SUBSYSTEM=="drm", ENV{WEDGED}=="rebind", DEVPATH=="*/drm/card[0-9]",
466 Recovery script::
470 DEVPATH=$(readlink -f /sys/$1/device)
472 DRIVER=$(readlink -f $DEVPATH/driver)
474 echo -n $DEVICE > $DRIVER/unbind
475 echo -n $DEVICE > $DRIVER/bind
478 -------------
480 Although basic recovery is possible with a simple script, consumers can define
481 custom policies around recovery. For example, if the driver supports multiple
482 recovery methods, consumers can opt for the suitable one depending on scenarios
485 recovery decision on the findings. This is useful especially when the driver is
486 unsure about recovery or method is unknown.
493 .. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
497 -------------------------------
520 E.g. root-only or much more common, DRM master-only operations return
532 when the exporting driver of a shared dma-buf or fence doesn't support a
546 Catch-all for anything that is an invalid argument combination which
554 .. kernel-doc:: include/drm/drm_ioctl.h
557 .. kernel-doc:: drivers/gpu/drm/drm_ioctl.c
560 .. kernel-doc:: drivers/gpu/drm/drm_ioc32.c
567 --------------------------------------
569 New cross-driver userspace interface extensions, like new IOCTL, new KMS
571 should have driver-agnostic testcases in IGT for that feature, if such a test
575 ---------------------------
581 https://gitlab.freedesktop.org/drm/igt-gpu-tools/.
584 --------------------------
586 VKMS is a software-only model of a KMS driver that is useful for testing
600 It's possible to run the IGT-tests in a VM in two ways:
606 the host machine to run igt-tests. This example uses virtme::
608 $ virtme-run --rwdir /path/for/shared_dir --kdir=path/for/kernel/directory --mods=auto
610 Run the igt-tests in the guest machine. This example runs the 'kms_flip'
613 $ /path/for/igt-gpu-tools/scripts/run-tests.sh -p -s -t "kms_flip.*" -v
616 (-p option). It creates an HTML summary of the test results and saves
617 them in the folder "igt-gpu-tools/results". It executes only the igt-tests
618 matching the -t option.
621 -------------------
623 .. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
626 .. kernel-doc:: drivers/gpu/drm/drm_debugfs_crc.c
630 ---------------
632 .. kernel-doc:: include/drm/drm_debugfs.h
635 .. kernel-doc:: drivers/gpu/drm/drm_debugfs.c
641 .. kernel-doc:: drivers/gpu/drm/drm_sysfs.c
644 .. kernel-doc:: drivers/gpu/drm/drm_sysfs.c
659 This was only used for user-mode-settind drivers around modesetting
661 mode setting, since on many devices the vertical blank counter is
663 call this any more since with kernel mode setting it is a no-op.
668 .. kernel-doc:: include/uapi/drm/drm_mode.h
674 ----------
684 .. kernel-doc:: include/uapi/drm/drm.h
687 .. kernel-doc:: include/uapi/drm/drm_mode.h
691 dma-buf interoperability
694 Please see Documentation/userspace-api/dma-buf-alloc-exchange.rst for
695 information on how dma-buf is integrated and exposed within DRM.