fishHEADmaster

1 files changed, 48 insertions, 0 deletions

diff --git a/backport-include/linux/fb.h b/backport-include/linux/fb.h
new file mode 100644
index 0000000..4522e25
--- /dev/null
+++ b/backport-include/linux/fb.h
@@ -0,0 +1,48 @@
+#ifndef __BACKPORT_FB_H
+#define __BACKPORT_FB_H
+#include_next <linux/fb.h>
+#include <linux/version.h>
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(3,10,0)
+/*
+ * This is a linux-next data structure element collateral evolution,
+ * we use a wrapper to avoid #ifdef hell to backport it. This allows
+ * us to use a simple fb_info_skip_vt_switch() replacement for when
+ * the new data structure element is used. If coccinelle SmPL grammar
+ * could be used to express the transformation for us on compat-drivers
+ * it means we'd need to express it only once. If the structure element
+ * collateral evolution were to be used *at development* time and we'd
+ * have a way to express the inverse through SmPL we'd be able to
+ * backport this collateral evolution automatically for any new driver
+ * that used it. We'd use coccinelle to look for it and do the
+ * transformations for us based on the original commit (maybe SmPL
+ * would be listed on the commit log.
+ *
+ * We may need the LINUX_BACKPORT() call that adds the backport_
+ * prefix for older kernels than 3.10 if distros decide to
+ * add this same static inline themselves (although unlikely).
+ */
+#define fb_enable_skip_vt_switch LINUX_BACKPORT(fb_enable_skip_vt_switch)
+static inline void fb_enable_skip_vt_switch(struct fb_info *info)
+{
+}
+#else /* kernel is >= 3.10 */
+/*
+ * We'd delete this upstream ever got this, we use our
+ * backport_ prefix with LINUX_BACKPORT() so that if this
+ * does get upstream we would not have to add another ifdef
+ * here for the kernels in between v3.10.. up to the point
+ * the routine would have gotten added, we'd just delete this
+ * #else condition completely. If we didn't have this and
+ * say 3.12 added the static inline upstream, we'd have a
+ * clash on the backport for 3.12 as the routine would
+ * already be defined *but* we'd need it for 3.11.
+ */
+#define fb_enable_skip_vt_switch LINUX_BACKPORT(fb_enable_skip_vt_switch)
+static inline void fb_enable_skip_vt_switch(struct fb_info *info)
+{
+	info->skip_vt_switch = true;
+}
+#endif /* LINUX_VERSION_CODE < KERNEL_VERSION(3,10,0) */
+
+#endif /* __BACKPORT_FB_H */