Re: [PATCH] drm/panfrost: Export all GPU feature registers
From: Alyssa Rosenzweig
Date: Wed Jul 24 2019 - 12:40:13 EST
This is definitely helpful!
My one concern is, supposing userspace really does need all of this
information, is it wasteful to have to do 30+ ioctls just to get this?
kbase had a single ioctl to grab all of the properties, whether
userspace wanted them or not. I'm not sure if that's better -- the two
approaches are rather polar opposites.
Granted this would be on driver init so not a critical path.
On Wed, Jul 24, 2019 at 10:27:03AM -0600, Rob Herring wrote:
> Adding Alyssa's Collabora email.
> On Wed, Jul 24, 2019 at 4:56 AM Steven Price <steven.price@xxxxxxx> wrote:
> > Midgard/Bifrost GPUs have a bunch of feature registers providing details
> > of what the hardware supports. Panfrost already reads these, this patch
> > exports them all to user space so that the jobs created by the user space
> > driver can be tuned for the particular hardware implementation.
> > Signed-off-by: Steven Price <steven.price@xxxxxxx>
> > ---
> > drivers/gpu/drm/panfrost/panfrost_device.h | 1 +
> > drivers/gpu/drm/panfrost/panfrost_drv.c | 38 +++++++++++++++++++--
> > drivers/gpu/drm/panfrost/panfrost_gpu.c | 2 ++
> > include/uapi/drm/panfrost_drm.h | 39 ++++++++++++++++++++++
> > 4 files changed, 77 insertions(+), 3 deletions(-)
> LGTM. I'll give it a bit more time to see if there are any comments
> before I apply it.
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