Render nodes provide an API for userspace to use non-privileged GPU
commands without any running DRM-Master. It is useful for offscreen
rendering, GPGPU clients, and normal render clients which do not perform
modesetting.
Compared to legacy clients, render clients no longer need any
authentication to perform client ioctls. Instead, user-space controls
render/client access to GPUs via filesystem access-modes on the
render-node. Once a render-node was opened, a client has full access to
the client/render operations on the GPU. However, no modesetting or ioctls
that affect global state are allowed on render nodes.
To prevent privilege-escalation, drivers must explicitly state that they
support render nodes. They must mark their render-only ioctls as
DRM_RENDER_ALLOW so render clients can use them. Furthermore, they must
support clients without any attached master.
If filesystem access-modes are not enough for fine-grained access control
to render nodes (very unlikely, considering the versaitlity of FS-ACLs),
you may still fall-back to fd-passing from server to client (which allows
arbitrary access-control). However, note that revoking access is
currently impossible and unlikely to get implemented.
Note: Render clients no longer have any associated DRM-Master as they are
supposed to be independent of any server state. DRM core highly depends on
file_priv->master to be non-NULL for modesetting/ctx/etc. commands.
Therefore, drivers must be very careful to not require DRM-Master if they
support DRIVER_RENDER.
So far render-nodes are protected by "drm_rnodes". As long as this
module-parameter is not set to 1, a driver will not create render nodes.
This allows us to experiment with the API a bit before we stabilize it.
v2: drop insecure GEM_FLINK to force use of dmabuf
Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
It's only used in drm_platform.c.
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Platform device drivers usually use the driver-private data for their
own purposes. Having it overwritten by drm_platform_init() is confusing
and error-prone.
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Convert #include "..." to #include <path/...> in drivers/gpu/.
Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Dave Jones <davej@redhat.com>
If there are not multiple instances of a platform device, the id
should apparently be set to -1. Which results in a odd looking
bus-id like "platform:foodrm:-1". Probably we should just treat
this case as id 0.
Signed-off-by: Rob Clark <rob@ti.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Include the device id in the bus-id to give userspace a way to open
the correct "cardN" when there are multiple device instances.
Signed-off-by: Rob Clark <rob@ti.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This abstracts the pci/platform interface out a step further,
we can go further but this is far enough for now to allow USB
to be plugged in.
The drivers now just call the init code directly for their
device type.
Signed-off-by: Dave Airlie <airlied@redhat.com>
Not 100% sure this is due to BKL removal, its most likely a combination
of that + userspace timing changes in udev/plymouth. The drm adds the sysfs
device before the driver has completed internal loading, this causes udev
to make the node and plymouth to open it before we've completed loading.
The proper solution is to delay the sysfs manipulation until later in loading
however this causes knock on issues with sysfs connector nodes, so we can use
the global mutex to serialise loading and userspace opens.
Reported-by: Toni Spets (hifi on #radeon)
Signed-off-by: Dave Airlie <airlied@redhat.com>
Allow platform devices without PCI resources to be DRM devices.
[airlied: fixup warnings with dev pointers]
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
