[PATCH 2/3] drm/vkms: Switch to shmem helpers
Thomas Zimmermann
tzimmermann at suse.de
Mon Oct 12 11:20:30 UTC 2020
On Mon, 12 Oct 2020 11:59:03 +0100 Chris Wilson <chris at chris-wilson.co.uk>
wrote:
> Quoting Daniel Vetter (2020-10-10 00:21:55)
> > Inspired by a patch by Chris Wilson for vgem. Plus this gives us vmap
> > at the gem bo level, which we need for generic fbdev emulation.
> >
> > Luckily shmem also tracks ->vaddr, so we just need to adjust the code
> > all over a bit to make this fit.
> >
> > Also wire up handle_to_fd, dunno why that was missing.
> >
> > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> > Cc: Maxime Ripard <mripard at kernel.org>
> > Cc: Thomas Zimmermann <tzimmermann at suse.de>
> > Cc: David Airlie <airlied at linux.ie>
> > Cc: Daniel Vetter <daniel at ffwll.ch>
> > Cc: Rodrigo Siqueira <rodrigosiqueiramelo at gmail.com>
> > Cc: Melissa Wen <melissa.srw at gmail.com>
> > Cc: Haneen Mohammed <hamohammed.sa at gmail.com>
> > ---
> > diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
> > index 33c031f27c2c..66c6842d70db 100644
> > --- a/drivers/gpu/drm/vkms/vkms_composer.c
> > +++ b/drivers/gpu/drm/vkms/vkms_composer.c
> > @@ -5,6 +5,7 @@
> > #include <drm/drm_atomic.h>
> > #include <drm/drm_atomic_helper.h>
> > #include <drm/drm_gem_framebuffer_helper.h>
> > +#include <drm/drm_gem_shmem_helper.h>
> > #include <drm/drm_vblank.h>
>
> > static void vkms_release(struct drm_device *dev)
> > {
> > @@ -91,9 +82,11 @@ static struct drm_driver vkms_driver = {
> > .driver_features = DRIVER_MODESET | DRIVER_ATOMIC | DRIVER_GEM,
> > .release = vkms_release,
> > .fops = &vkms_driver_fops,
> > - .dumb_create = vkms_dumb_create,
> > + .dumb_create = drm_gem_shmem_dumb_create,
>
> Something worth pointing out is that will create an uncached (well WC)
> buffer, but since it is being exported with prime, that is probably for
I'd rather set .gem_create_object to drm_gem_shmem_create_object_cached() to
get cached memory. We already have other drivers that do this.
Best regards
Thomas
> the better. It might be worth using a memcpy_from_wc() for writeback/CRC
> calculations. E.g.
>
> > @@ -129,15 +130,15 @@ static void compose_cursor(struct vkms_composer *cursor_composer,
> > void *vaddr_out)
> > {
> > + blend(vaddr_out, cursor_shmem_obj->vaddr,
> > primary_composer, cursor_composer);
> > }
> >
> > @@ -147,20 +148,20 @@ static int compose_planes(void **vaddr_out,
> > {
> > + memcpy(*vaddr_out, shmem_obj->vaddr, shmem_obj->base.size);
>
> would benefit from WC accessors.
>
> On the other hand, if the load is so small no one notices, it can wait.
>
> Do we have anything that uses vkms in CI?
>
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> -Chris
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