[Buildroot] [PATCH] package/sunxi-mali-mainline-driver: update help section to make it work on Linux >= 4.20

[Giulio Benetti]

On Linux version >= 4.20 we need to pass
drm_kms_helper.drm_leak_fbdev_smem=1 to make this driver to work.

Signed-off-by: Giulio Benetti <giulio.benetti at benettiengineering.com>
---
 package/sunxi-mali-mainline-driver/Config.in | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/package/sunxi-mali-mainline-driver/Config.in b/package/sunxi-mali-mainline-driver/Config.in
index 5db66c5bf6..9bc80944fb 100644
--- a/package/sunxi-mali-mainline-driver/Config.in
+++ b/package/sunxi-mali-mainline-driver/Config.in
@@ -25,5 +25,8 @@ config BR2_PACKAGE_SUNXI_MALI_MAINLINE_DRIVER
 	  starting from Linux Kernel >= 4.20 following options must be
 	  enabled:
 	  - CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM
+	  and following kernel command-line must be passed:
+	  `drm_kms_helper.drm_leak_fbdev_smem=1`
+	  since drm_kms_helper.drm_leak_fbdev_smem is set to 0 by default
 
 	  https://github.com/mripard/sunxi-mali/blob/master/README.md
-- 
2.25.1