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18ace11f87
We wish to control certain driver_features flags on a per-device basis
while still sharing a single drm_driver instance across all the
devices. To that end introduce device.driver_features. By default
it will be set to ~0 to not impose any limits beyond
driver.driver_features. Drivers can then clear specific flags
in the per-device bitmask to limit the capabilities of the device.
An alternative approach would be to copy the driver_features from
the driver into the device in drm_dev_init(), however that would
require verifying that no driver is currently changing
driver.driver_features after drm_dev_init(). Hence the ~0 apporach
was easier.
Ideally we'd also make drm_driver const but there is plenty of code
left that wants to mutate it (eg. various vfunc assignments). We'll
need to fix all that up before we can make it const.
And while at it fix up the type of the feature flag passed to
drm_core_check_feature().
v2: Streamline the && vs. & (Chris)
s/int/u32/ in drm_core_check_feature() args
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180913131622.17690-1-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reviewed-by: Michel Dänzer <michel.daenzer@amd.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.