Apparently drivers need to check all this stuff themselves, which for
most things makes sense I guess. And for everything else we luck out,
because modern distros stopped supporting any other fbdev drivers than
drm ones and I really don't want to argue anymore about who needs to
check stuff. Therefore fixing all this just for drm fbdev emulation is
good enough.
Note that var->active is not set or validated. This is just control
flow for fbmem.c and needs to be validated in there as needed.
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Cc: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Cc: Maxime Ripard <mripard@xxxxxxxxxx>
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/drm_fb_helper.c | 49 +++++++++++++++++++++++++--------
1 file changed, 38 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index b9696d13a741..ef4eb8b12766 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -1543,6 +1543,27 @@ static void drm_fb_helper_fill_pixel_fmt(struct fb_var_screeninfo *var,
}
}
+static void __fill_var(struct fb_var_screeninfo *var,
+ struct drm_framebuffer *fb)
+{
+ int i;
+
+ var->xres_virtual = fb->width;
+ var->yres_virtual = fb->height;
+ var->accel_flags = FB_ACCELF_TEXT;
+ var->bits_per_pixel = drm_format_info_bpp(fb->format, 0);
+
+ var->height = var->width = 0;
+ var->left_margin = var->right_margin = 0;
+ var->upper_margin = var->lower_margin = 0;
+ var->hsync_len = var->vsync_len = 0;
+ var->sync = var->vmode = 0;
+ var->rotate = 0;
+ var->colorspace = 0;
+ for (i = 0; i < 4; i++)
+ var->reserved[i] = 0;
+}
+
/**
* drm_fb_helper_check_var - implementation for &fb_ops.fb_check_var
* @var: screeninfo to check
@@ -1595,8 +1616,22 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
return -EINVAL;
}
- var->xres_virtual = fb->width;
- var->yres_virtual = fb->height;
+ __fill_var(var, fb);
+
+ /*
+ * fb_pan_display() validates this, but fb_set_par() doesn't and just
+ * falls over. Note that __fill_var above adjusts y/res_virtual.
+ */
+ if (var->yoffset > var->yres_virtual - var->yres ||
+ var->xoffset > var->xres_virtual - var->xres)
+ return -EINVAL;
+
+ /* We neither support grayscale nor FOURCC (also stored in here). */
+ if (var->grayscale > 0)
+ return -EINVAL;
+
+ if (var->nonstd)
+ return -EINVAL;
/*
* Workaround for SDL 1.2, which is known to be setting all pixel format
@@ -1612,11 +1647,6 @@ int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
drm_fb_helper_fill_pixel_fmt(var, format);
}
- /*
- * Likewise, bits_per_pixel should be rounded up to a supported value.
- */
- var->bits_per_pixel = bpp;
-
/*
* drm fbdev emulation doesn't support changing the pixel format at all,
* so reject all pixel format changing requests.
@@ -2040,12 +2070,9 @@ static void drm_fb_helper_fill_var(struct fb_info *info,
}
info->pseudo_palette = fb_helper->pseudo_palette;
- info->var.xres_virtual = fb->width;
- info->var.yres_virtual = fb->height;
- info->var.bits_per_pixel = drm_format_info_bpp(format, 0);
- info->var.accel_flags = FB_ACCELF_TEXT;
info->var.xoffset = 0;
info->var.yoffset = 0;
+ __fill_var(&info->var, fb);
info->var.activate = FB_ACTIVATE_NOW;
drm_fb_helper_fill_pixel_fmt(&info->var, format);
--
2.40.0
