From: Eric Anholt <eric@anholt.net>
To: Paul Kocialkowski <paul.kocialkowski@bootlin.com>,
dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
Maxime Ripard <maxime.ripard@bootlin.com>,
Sean Paul <sean@poorly.run>, David Airlie <airlied@linux.ie>,
Daniel Vetter <daniel@ffwll.ch>,
Eben Upton <eben@raspberrypi.org>,
Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Subject: Re: [PATCH v2 1/2] drm/file: Rehabilitate the firstopen hook for non-legacy drivers
Date: Thu, 21 Mar 2019 16:12:35 -0700 [thread overview]
Message-ID: <87sgvfsty4.fsf@anholt.net> (raw)
In-Reply-To: <82618ee8c2a2380a62b1fb894e5c35c602e20f3d.camel@bootlin.com>
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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.
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next prev parent reply other threads:[~2019-03-21 23:12 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 15:48 [PATCH v2 0/2] drm/vc4: Binner BO management improvements Paul Kocialkowski
2019-03-20 15:48 ` [PATCH v2 1/2] drm/file: Rehabilitate the firstopen hook for non-legacy drivers Paul Kocialkowski
2019-03-20 16:56 ` Eric Anholt
2019-03-21 15:27 ` Paul Kocialkowski
2019-03-21 23:12 ` Eric Anholt [this message]
2019-03-28 18:53 ` Daniel Vetter
2019-03-29 9:09 ` Daniel Stone
2019-03-29 15:02 ` Paul Kocialkowski
2019-03-29 15:25 ` Daniel Vetter
2019-03-29 15:49 ` Paul Kocialkowski
2019-03-29 18:14 ` Eric Anholt
2019-03-29 18:42 ` Daniel Stone
2019-03-29 20:21 ` Paul Kocialkowski
2019-03-29 15:07 ` Paul Kocialkowski
2019-03-20 15:48 ` [PATCH v2 2/2] drm/vc4: Allocated/liberate the binner BO at firstopen/lastclose Paul Kocialkowski
2019-03-20 16:58 ` Eric Anholt
2019-03-21 15:58 ` Paul Kocialkowski
2019-03-21 16:20 ` Eric Anholt
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