Linux Virtualization - Sep 2018 - [PATCH v2 5/6] drm/bochs: fix DRM_FORMAT_* handling for big endian machines.

Use DRM_FORMAT_HOST_XRGB8888, so we are using the correct format code
on bigendian machines.  Also set the quirk_addfb_prefer_host_byte_order
mode_config bit so drm_mode_addfb() asks for the correct format code.

Create our own plane and use drm_crtc_init_with_planes() instead of
depending on the default created by drm_crtc_init().  That way the plane
format list is correct on bigendian machines.

With this patch applied both ADDFB and ADDFB2 ioctls work correctly in
the bochs-drm.ko driver on big endian machines.  Without the patch only
ADDFB (which still seems to be used by the majority of userspace) works
correctly.

Signed-off-by: Gerd Hoffmann <kraxel at redhat.com>
---
 drivers/gpu/drm/bochs/bochs_fbdev.c |  5 ++---
 drivers/gpu/drm/bochs/bochs_kms.c   | 34 +++++++++++++++++++++++++++++++++-
 drivers/gpu/drm/bochs/bochs_mm.c    |  2 +-
 3 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bochs/bochs_fbdev.c
b/drivers/gpu/drm/bochs/bochs_fbdev.c
index 14eb8d0d5a..bf728790fa 100644
--- a/drivers/gpu/drm/bochs/bochs_fbdev.c
+++ b/drivers/gpu/drm/bochs/bochs_fbdev.c
@@ -64,9 +64,8 @@ static int bochsfb_create(struct drm_fb_helper *helper,
 
 	mode_cmd.width = sizes->surface_width;
 	mode_cmd.height = sizes->surface_height;
-	mode_cmd.pitches[0] = mode_cmd.width * ((sizes->surface_bpp + 7) / 8);
-	mode_cmd.pixel_format = drm_mode_legacy_fb_format(sizes->surface_bpp,
-							  sizes->surface_depth);
+	mode_cmd.pitches[0] = sizes->surface_width * 4;
+	mode_cmd.pixel_format = DRM_FORMAT_HOST_XRGB8888;
 	size = mode_cmd.pitches[0] * mode_cmd.height;
 
 	/* alloc, pin & map bo */
diff --git a/drivers/gpu/drm/bochs/bochs_kms.c
b/drivers/gpu/drm/bochs/bochs_kms.c
index ca5a9afdd5..b40077d04b 100644
--- a/drivers/gpu/drm/bochs/bochs_kms.c
+++ b/drivers/gpu/drm/bochs/bochs_kms.c
@@ -129,12 +129,43 @@ static const struct drm_crtc_helper_funcs
bochs_helper_funcs = {
 	.commit = bochs_crtc_commit,
 };
 
+static const uint32_t bochs_formats[] = {
+	DRM_FORMAT_HOST_XRGB8888,
+};
+
+static struct drm_plane *bochs_primary_plane(struct drm_device *dev)
+{
+	struct drm_plane *primary;
+	int ret;
+
+	primary = kzalloc(sizeof(*primary), GFP_KERNEL);
+	if (primary == NULL) {
+		DRM_DEBUG_KMS("Failed to allocate primary plane\n");
+		return NULL;
+	}
+
+	ret = drm_universal_plane_init(dev, primary, 0,
+				       &drm_primary_helper_funcs,
+				       bochs_formats,
+				       ARRAY_SIZE(bochs_formats),
+				       NULL,
+				       DRM_PLANE_TYPE_PRIMARY, NULL);
+	if (ret) {
+		kfree(primary);
+		primary = NULL;
+	}
+
+	return primary;
+}
+
 static void bochs_crtc_init(struct drm_device *dev)
 {
 	struct bochs_device *bochs = dev->dev_private;
 	struct drm_crtc *crtc = &bochs->crtc;
+	struct drm_plane *primary = bochs_primary_plane(dev);
 
-	drm_crtc_init(dev, crtc, &bochs_crtc_funcs);
+	drm_crtc_init_with_planes(dev, crtc, primary, NULL,
+				  &bochs_crtc_funcs, NULL);
 	drm_crtc_helper_add(crtc, &bochs_helper_funcs);
 }
 
@@ -253,6 +284,7 @@ int bochs_kms_init(struct bochs_device *bochs)
 	bochs->dev->mode_config.fb_base = bochs->fb_base;
 	bochs->dev->mode_config.preferred_depth = 24;
 	bochs->dev->mode_config.prefer_shadow = 0;
+	bochs->dev->mode_config.quirk_addfb_prefer_host_byte_order = true;
 
 	bochs->dev->mode_config.funcs = &bochs_mode_funcs;
 
diff --git a/drivers/gpu/drm/bochs/bochs_mm.c b/drivers/gpu/drm/bochs/bochs_mm.c
index c9c7097030..fdf151fbdb 100644
--- a/drivers/gpu/drm/bochs/bochs_mm.c
+++ b/drivers/gpu/drm/bochs/bochs_mm.c
@@ -506,7 +506,7 @@ bochs_user_framebuffer_create(struct drm_device *dev,
 	       (mode_cmd->pixel_format >> 16) & 0xff,
 	       (mode_cmd->pixel_format >> 24) & 0xff);
 
-	if (mode_cmd->pixel_format != DRM_FORMAT_XRGB8888)
+	if (mode_cmd->pixel_format != DRM_FORMAT_HOST_XRGB8888)
 		return ERR_PTR(-ENOENT);
 
 	obj = drm_gem_object_lookup(filp, mode_cmd->handles[0]);
-- 
2.9.3