DRM drivers will be able to handle deferred I/O by themselves. So
a driver will be able to use deferred I/O without an intermediate
shadow buffer.
Prepare fbdev emulation by separating shadow buffers and deferred
I/O from each other.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 35 ++++++++++++++++++++++++++++-----
1 file changed, 30 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index dd1d72d58b35..660ec5038c4e 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -660,6 +660,19 @@ static bool drm_fbdev_use_shadow_fb(struct drm_fb_helper *fb_helper)
fb->funcs->dirty;
}
+static bool drm_fbdev_use_deferred_io(struct drm_fb_helper *fb_helper)
+{
+ struct drm_framebuffer *fb = fb_helper->fb;
+
+ /*
+ * Any driver with damage handling requires deferred I/O to
+ * keep track of the updated screen areas. Drivers with shadow
+ * buffers need deferred I/O to forward screen updates to the
+ * buffer object.
+ */
+ return fb->funcs->dirty || drm_fbdev_use_shadow_fb(fb_helper);
+}
+
static void drm_fb_helper_damage(struct fb_info *info, u32 x, u32 y,
u32 width, u32 height)
{
@@ -667,7 +680,7 @@ static void drm_fb_helper_damage(struct fb_info *info, u32 x, u32 y,
struct drm_clip_rect *clip = &helper->damage_clip;
unsigned long flags;
- if (!drm_fbdev_use_shadow_fb(helper))
+ if (!drm_fbdev_use_deferred_io(helper))
return;
spin_lock_irqsave(&helper->damage_lock, flags);
@@ -2119,8 +2132,16 @@ static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
struct drm_fb_helper *fb_helper = info->par;
if (drm_fbdev_use_shadow_fb(fb_helper))
+ /*
+ * Drivers with shadow buffer use fbdev's implementation of
+ * deferred I/O.
+ */
return fb_deferred_io_mmap(info, vma);
else if (fb_helper->dev->driver->gem_prime_mmap)
+ /*
+ * Either directly mmap'ed or with deferred I/O; drivers
+ * without shadow buffer handle mmap themselves.
+ */
return fb_helper->dev->driver->gem_prime_mmap(fb_helper->buffer->gem, vma);
else
return -ENODEV;
@@ -2131,7 +2152,9 @@ static bool drm_fbdev_use_iomem(struct fb_info *info)
struct drm_fb_helper *fb_helper = info->par;
struct drm_client_buffer *buffer = fb_helper->buffer;
- return !drm_fbdev_use_shadow_fb(fb_helper) && buffer->map.is_iomem;
+ if (drm_fbdev_use_shadow_fb(fb_helper))
+ return false;
+ return buffer->map.is_iomem;
}
static ssize_t fb_read_screen_base(struct fb_info *info, char __user *buf, size_t count,
@@ -2396,9 +2419,6 @@ static int drm_fb_helper_generic_probe(struct drm_fb_helper *fb_helper,
if (!fbi->screen_buffer)
return -ENOMEM;
fbi->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
-
- fbi->fbdefio = &drm_fbdev_defio;
- fb_deferred_io_init(fbi);
} else {
/* buffer is mapped for HW framebuffer */
ret = drm_client_buffer_vmap(fb_helper->buffer, &map);
@@ -2424,6 +2444,11 @@ static int drm_fb_helper_generic_probe(struct drm_fb_helper *fb_helper,
#endif
}
+ if (drm_fbdev_use_deferred_io(fb_helper)) {
+ fbi->fbdefio = &drm_fbdev_defio;
+ fb_deferred_io_init(fbi);
+ }
+
return 0;
}
--
2.35.1
