Re: [Intel-gfx] [PATCH RFC 3/3] drm/i915/display: Implement fb_mmap callback function

[Andrzej Hajda]

On 20.03.2023 11:09, Nirmoy Das wrote:

If stolen memory allocation fails for fbdev, the driver will
fallback to system memory. Calculation of smem_start is wrong
for such framebuffer objs if the platform comes with no gmadr or
no aperture. Solve this by adding fb_mmap callback which will
use GTT if aperture is available otherwise will use cpu to access
the framebuffer.

v2: Use to_intel_fbdev() function(Jani)

Cc: Matthew Auld <matthew.a...@intel.com>
Cc: Andi Shyti <andi.sh...@linux.intel.com>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Cc: Jani Nikula <jani.nik...@intel.com>
Cc: Imre Deak <imre.d...@intel.com>
Signed-off-by: Nirmoy Das <nirmoy....@intel.com>
Reviewed-by: Andi Shyti <andi.sh...@linux.intel.com>

Reviewed-by: Andrzej Hajda <andrzej.ha...@intel.com>

Regards
Andrzej

---
  drivers/gpu/drm/i915/display/intel_fbdev.c | 12 ++++++++++++
  1 file changed, 12 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c 
b/drivers/gpu/drm/i915/display/intel_fbdev.c
index 8c3b3c3fd0e0..5e52bef868a0 100644
--- a/drivers/gpu/drm/i915/display/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
@@ -40,8 +40,10 @@
  #include <drm/drm_crtc.h>
  #include <drm/drm_fb_helper.h>
  #include <drm/drm_fourcc.h>
+#include <drm/drm_gem_framebuffer_helper.h>

#include "gem/i915_gem_lmem.h"

+#include "gem/i915_gem_mman.h"

#include "i915_drv.h"

  #include "intel_display_types.h"
@@ -119,6 +121,15 @@ static int intel_fbdev_pan_display(struct 
fb_var_screeninfo *var,
        return ret;
  }

+static int intel_fbdev_mmap(struct fb_info *info, struct vm_area_struct *vma)

+{
+       struct intel_fbdev *fbdev = to_intel_fbdev(info->par);
+       struct drm_gem_object *bo = drm_gem_fb_get_obj(&fbdev->fb->base, 0);
+       struct drm_i915_gem_object *obj = to_intel_bo(bo);
+
+       return i915_gem_fb_mmap(obj, vma);
+}
+
  static const struct fb_ops intelfb_ops = {
        .owner = THIS_MODULE,
        DRM_FB_HELPER_DEFAULT_OPS,
@@ -130,6 +141,7 @@ static const struct fb_ops intelfb_ops = {
        .fb_imageblit = drm_fb_helper_cfb_imageblit,
        .fb_pan_display = intel_fbdev_pan_display,
        .fb_blank = intel_fbdev_blank,
+       .fb_mmap = intel_fbdev_mmap,
  };

static int intelfb_alloc(struct drm_fb_helper *helper,