drm/tegra: fb: Implement ->fb_mmap() callback (b8f3f500) · Commits · 戴 / test

This fixes hangs with legacy applications that use the mmap() syscall on the fbdev device to map framebuffer memory. The fbdev implementation for mmap() creates a mapping that conflicts with DRM usage and causes a hang when the memory is accessed through the mapping. Reported-by:

Marcel Ziswiler <marcel.ziswiler@toradex.com> Signed-off-by:

Thierry Reding <treding@nvidia.com> Tested-by:

Stefan Agner <stefan@agner.ch> Tested-by:

Marcel Ziswiler <marcel.ziswiler@toradex.com> Reported-by:

Marcel Ziswiler <marcel.ziswiler@toradex.com> Signed-off-by:

Thierry Reding <treding@nvidia.com>

drivers/gpu/drm/tegra/fb.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -224,12 +224,28 @@ unreference:
		}

		#ifdef CONFIG_DRM_FBDEV_EMULATION
		static int tegra_fb_mmap(struct fb_info info, struct vm_area_struct vma)
		{
		struct drm_fb_helper *helper = info->par;
		struct tegra_bo *bo;
		int err;

		bo = tegra_fb_get_plane(helper->fb, 0);

		err = drm_gem_mmap_obj(&bo->gem, bo->gem.size, vma);
		if (err < 0)
		return err;

		return __tegra_gem_mmap(&bo->gem, vma);
		}

		static struct fb_ops tegra_fb_ops = {
		.owner = THIS_MODULE,
		DRM_FB_HELPER_DEFAULT_OPS,
		.fb_fillrect = drm_fb_helper_sys_fillrect,
		.fb_copyarea = drm_fb_helper_sys_copyarea,
		.fb_imageblit = drm_fb_helper_sys_imageblit,
		.fb_mmap = tegra_fb_mmap,
		};

		static int tegra_fbdev_probe(struct drm_fb_helper *helper,

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