From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Kocialkowski Subject: Re: [PATCH v3 1/2] drm/file: Rehabilitate the firstopen hook for non-legacy drivers Date: Fri, 29 Mar 2019 09:38:19 +0100 Message-ID: <95645eb463840faf32bae284c16af443cc62f8a8.camel@bootlin.com> References: <20190328161306.22757-1-paul.kocialkowski@bootlin.com> <20190328161306.22757-2-paul.kocialkowski@bootlin.com> <20190329083534.GC2665@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20190329083534.GC2665@phenom.ffwll.local> Sender: linux-kernel-owner@vger.kernel.org To: Daniel Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Maarten Lankhorst , Maxime Ripard , Sean Paul , David Airlie , Eric Anholt , Eben Upton , Thomas Petazzoni List-Id: dri-devel@lists.freedesktop.org Hi Daniel, On Fri, 2019-03-29 at 09:35 +0100, Daniel Vetter wrote: > On Thu, Mar 28, 2019 at 05:13:05PM +0100, Paul Kocialkowski wrote: > > 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 > > Reviewed-by: Eric Anholt > > --- > > drivers/gpu/drm/drm_file.c | 3 +-- > > include/drm/drm_drv.h | 3 --- > > 2 files changed, 1 insertion(+), 5 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) { > > If you guys insist on this (still not a fan myself) pls pull it out of > drm_setup - that's all just legacy hw setup in there. I still think > tracking this a bit more accurately (if you want to bother with this) > would be better. I sent out this v3 right before receiving your comments on v2, so this new iteration only takes Eric's comments into account. I think the points you made on v2 are very legitimate and I'll be working to prepare a new series that takes them into consideration :) Cheers, Paul > -Daniel > > > 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..de5637494503 100644 > > --- a/include/drm/drm_drv.h > > +++ b/include/drm/drm_drv.h > > @@ -234,9 +234,6 @@ struct drm_driver { > > * kernel driver does not really own the hardware. Instead ownershipe is > > * handled with the help of userspace through an inheritedly racy dance > > * 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. > > */ > > void (*lastclose) (struct drm_device *); > > > > -- > > 2.21.0 > > -- Paul Kocialkowski, Bootlin Embedded Linux and kernel engineering https://bootlin.com