linux-kernel - Re: [PATCH v2 2/2] drm/komeda: Adds komeda_kms_drop_master

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Date:   Wed, 12 Jun 2019 02:26:24 +0000
From:   "james qian wang (Arm Technology China)" <james.qian.wang@....com>
To:     "Lowry Li (Arm Technology China)" <Lowry.Li@....com>,
        Liviu Dudau <Liviu.Dudau@....com>,
        "maarten.lankhorst@...ux.intel.com" 
        <maarten.lankhorst@...ux.intel.com>,
        "seanpaul@...omium.org" <seanpaul@...omium.org>,
        "airlied@...ux.ie" <airlied@...ux.ie>,
        Brian Starkey <Brian.Starkey@....com>,
        Ayan Halder <Ayan.Halder@....com>,
        "Jonathan Chai (Arm Technology China)" <Jonathan.Chai@....com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "Julien Yin (Arm Technology China)" <Julien.Yin@....com>,
        nd <nd@....com>
Subject: Re: [PATCH v2 2/2] drm/komeda: Adds komeda_kms_drop_master

On Tue, Jun 11, 2019 at 02:30:38PM +0200, Daniel Vetter wrote:
> On Tue, Jun 11, 2019 at 11:13:45AM +0000, Lowry Li (Arm Technology China) wrote:
> > From: "Lowry Li (Arm Technology China)" <Lowry.Li@....com>
> >
> > The komeda internal resources (pipelines) are shared between crtcs,
> > and resources release by disable_crtc. This commit is working for once
> > user forgot disabling crtc like app quit abnomally, and then the
> > resources can not be used by another crtc. Adds drop_master to
> > shutdown the device and make sure all the komeda resources have been
> > released and can be used for the next usage.
> >
> > Signed-off-by: Lowry Li (Arm Technology China) <lowry.li@....com>
> > ---
> >  drivers/gpu/drm/arm/display/komeda/komeda_kms.c | 13 +++++++++++++
> >  1 file changed, 13 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > index 8543860..647bce5 100644
> > --- a/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > +++ b/drivers/gpu/drm/arm/display/komeda/komeda_kms.c
> > @@ -54,11 +54,24 @@ static irqreturn_t komeda_kms_irq_handler(int irq, void *data)
> >  return status;
> >  }
> >
> > +/* Komeda internal resources (pipelines) are shared between crtcs, and resources
> > + * are released by disable_crtc. But if user forget disabling crtc like app quit
> > + * abnormally, the resources can not be used by another crtc.
> > + * Use drop_master to shutdown the device and make sure all the komeda resources
> > + * have been released, and can be used for the next usage.
> > + */
>
> No. If we want this, we need to implement this across drivers, not with
> per-vendor hacks.
>
> The kerneldoc should have been a solid hint: "Only used by vmwgfx."
> -Daniel

Hi Daniel:
This drop_master is really what we want, can we update the doc and
add komeda as a user of this hacks like "used by vmwfgx and komeda",
or maybe directly promote this per-vendor hacks as an optional chip
function ?

James

> > +static void komeda_kms_drop_master(struct drm_device *dev,
> > +   struct drm_file *file_priv)
> > +{
> > +drm_atomic_helper_shutdown(dev);
> > +}
> > +
> >  static struct drm_driver komeda_kms_driver = {
> >  .driver_features = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC |
> >     DRIVER_PRIME | DRIVER_HAVE_IRQ,
> >  .lastclose= drm_fb_helper_lastclose,
> >  .irq_handler= komeda_kms_irq_handler,
> > +.master_drop= komeda_kms_drop_master,
> >  .gem_free_object_unlocked= drm_gem_cma_free_object,
> >  .gem_vm_ops= &drm_gem_cma_vm_ops,
> >  .dumb_create= komeda_gem_cma_dumb_create,
> > --
> > 1.9.1
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@...ts.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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