lkml.org 
[lkml]   [2019]   [Mar]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v2 1/2] drm/file: Rehabilitate the firstopen hook for non-legacy drivers
Date
Paul Kocialkowski <paul.kocialkowski@bootlin.com> writes:

> Hi,
>
> Le mercredi 20 mars 2019 à 09:56 -0700, Eric Anholt a écrit :
>> Paul Kocialkowski <paul.kocialkowski@bootlin.com> writes:
>>
>> > The firstopen DRM driver hook was initially used to perform hardware
>> > initialization, which is now considered legacy. Only a single user of
>> > firstopen remains at this point (savage).
>> >
>> > In some specific cases, non-legacy drivers may also need to implement
>> > these hooks. For instance on VC4, we need to allocate a 16 MiB buffer
>> > for the GPU. Because it's not required for fbcon, it's a waste to
>> > allocate it before userspace starts using the DRM device.
>> >
>> > Using firstopen and lastclose for this allocation seems like the best
>> > fit, so re-habilitate the hook to allow it to be called for non-legacy
>> > drivers.
>> >
>> > Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
>> > ---
>> > drivers/gpu/drm/drm_file.c | 3 +--
>> > include/drm/drm_drv.h | 2 +-
>> > 2 files changed, 2 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/drm_file.c b/drivers/gpu/drm/drm_file.c
>> > index b1838a41ad43..c011b5cbfb6b 100644
>> > --- a/drivers/gpu/drm/drm_file.c
>> > +++ b/drivers/gpu/drm/drm_file.c
>> > @@ -266,8 +266,7 @@ static int drm_setup(struct drm_device * dev)
>> > {
>> > int ret;
>> >
>> > - if (dev->driver->firstopen &&
>> > - drm_core_check_feature(dev, DRIVER_LEGACY)) {
>> > + if (dev->driver->firstopen) {
>> > ret = dev->driver->firstopen(dev);
>> > if (ret != 0)
>> > return ret;
>> > diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
>> > index ca46a45a9cce..aa14607e54d4 100644
>> > --- a/include/drm/drm_drv.h
>> > +++ b/include/drm/drm_drv.h
>> > @@ -236,7 +236,7 @@ struct drm_driver {
>> > * to set/unset the VT into raw mode.
>> > *
>> > * Legacy drivers initialize the hardware in the @firstopen callback,
>> > - * which isn't even called for modern drivers.
>> > + * modern drivers can use it for other purposes only.
>> > */
>> > void (*lastclose) (struct drm_device *);
>>
>> Our usage in vc4 is not very different from what we called "hardware
>> initialization" in other devices. I would rather just delete this
>> sentence entirely.
>
> Sounds good to me!

With the delete, the series is:

Reviewed-by: Eric Anholt <eric@anholt.net>

but hopefully someone other than a vc4 developer (danvet?) can make the
call on whether undeprecating firstopen/lastclose for this is
reasonable.
[unhandled content-type:application/pgp-signature]
\
 
 \ /
  Last update: 2019-03-22 00:13    [W:0.065 / U:22.876 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site