drm: fix drm_mode_addfb() on big endian machines.

Userspace on big endian machhines typically expects the ADDFB ioctl
returns a big endian framebuffer.  drm_mode_addfb() will call
drm_mode_addfb2() unconditionally with little endian DRM_FORMAT_*
values though, which is wrong.  This patch fixes that.

Drivers (both kernel and xorg) have quirks in place to deal with the
broken drm_mode_addfb() behavior.  Because of this we can't just change
drm_mode_addfb() behavior for everybody without breaking things.  Add
the quirk_addfb_prefer_host_byte_order field to mode_config, so drivers
can opt-in.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20180905060445.15008-5-kraxel@redhat.com

diff --git a/drivers/gpu/drm/drm_framebuffer.c b/drivers/gpu/drm/drm_framebuffer.c
index 888c4d53cf23ba7f9be180196a147b314e26f31f..f863f8a20f8cd346834d56af47c3dc2074f196b7 100644 (file)
--- a/drivers/gpu/drm/drm_framebuffer.c
+++ b/drivers/gpu/drm/drm_framebuffer.c
@@ -124,6 +124,17 @@ int drm_mode_addfb(struct drm_device *dev, struct drm_mode_fb_cmd *or,
            r.pixel_format == DRM_FORMAT_XRGB2101010)
                r.pixel_format = DRM_FORMAT_XBGR2101010;
 
+       if (dev->mode_config.quirk_addfb_prefer_host_byte_order) {
+               if (r.pixel_format == DRM_FORMAT_XRGB8888)
+                       r.pixel_format = DRM_FORMAT_HOST_XRGB8888;
+               if (r.pixel_format == DRM_FORMAT_ARGB8888)
+                       r.pixel_format = DRM_FORMAT_HOST_ARGB8888;
+               if (r.pixel_format == DRM_FORMAT_RGB565)
+                       r.pixel_format = DRM_FORMAT_HOST_RGB565;
+               if (r.pixel_format == DRM_FORMAT_XRGB1555)
+                       r.pixel_format = DRM_FORMAT_HOST_XRGB1555;
+       }
+
        ret = drm_mode_addfb2(dev, &r, file_priv);
        if (ret)
                return ret;

diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
index 5d29f4ba6f69f9202d4f1fc7b23b869943a8da2c..928e4172a0bbe277058f5c791cfa9070eca9a9ca 100644 (file)
--- a/include/drm/drm_mode_config.h
+++ b/include/drm/drm_mode_config.h
@@ -811,6 +811,20 @@ struct drm_mode_config {
        uint32_t preferred_depth, prefer_shadow;
        bool quirk_addfb_prefer_xbgr_30bpp;
 
+       /**
+        * @quirk_addfb_prefer_host_byte_order:
+        *
+        * When set to true drm_mode_addfb() will pick host byte order
+        * pixel_format when calling drm_mode_addfb2().  This is how
+        * drm_mode_addfb() should have worked from day one.  It
+        * didn't though, so we ended up with quirks in both kernel
+        * and userspace drivers to deal with the broken behavior.
+        * Simply fixing drm_mode_addfb() unconditionally would break
+        * these drivers, so add a quirk bit here to allow drivers
+        * opt-in.
+        */
+       bool quirk_addfb_prefer_host_byte_order;
+
        /**
         * @async_page_flip: Does this device support async flips on the primary
         * plane?