[PATCH v2 1/1] util/grub.d/00_header.in: Disable loading all_video for EFI

[Andrew Hamilton <adhamilt@gmail.com>]

Loading all_video for EFI can cause video issues in some cases
since GRUB Bochs/Cirrus drivers may conflict with native EFI drivers.
Change default behavior for EFI to only load EFI specific video
modules. Also include a new environment variable to restore the old
behavior if needed.

Fixes: https://savannah.gnu.org/bugs/index.php?66200

Signed-off-by: Andrew Hamilton <adhamilt@gmail.com>
---
 docs/grub.texi           |  7 +++++++
 util/grub-mkconfig.in    |  3 ++-
 util/grub.d/00_header.in | 16 +++++++++++++++-
 3 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/docs/grub.texi b/docs/grub.texi
index 5b23ae47b..1ec5d3566 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -1642,6 +1642,13 @@ This option is unset by default, and is deprecated in favour of the less
 confusing @samp{GRUB_TIMEOUT_STYLE=countdown} or
 @samp{GRUB_TIMEOUT_STYLE=hidden}.
 
+@item GRUB_FORCE_EFI_ALL_VIDEO
+When set to true, this will allow grub-mkconfig to generate a GRUB config
+that supports loading the all_video module on the EFI platform instead of
+just the efi_gop and efi_uga modules.
+
+This option is unset by default.
+
 @end table
 
 For more detailed customisation of @command{grub-mkconfig}'s output, you may
diff --git a/util/grub-mkconfig.in b/util/grub-mkconfig.in
index 32c480dae..45787a1d1 100644
--- a/util/grub-mkconfig.in
+++ b/util/grub-mkconfig.in
@@ -255,7 +255,8 @@ export GRUB_DEFAULT \
   GRUB_ENABLE_CRYPTODISK \
   GRUB_BADRAM \
   GRUB_OS_PROBER_SKIP_LIST \
-  GRUB_DISABLE_SUBMENU
+  GRUB_DISABLE_SUBMENU \
+  GRUB_FORCE_EFI_ALL_VIDEO
 
 if test "x${grub_cfg}" != "x"; then
   rm -f "${grub_cfg}.new"
diff --git a/util/grub.d/00_header.in b/util/grub.d/00_header.in
index 9d36feda3..77834cfaf 100644
--- a/util/grub.d/00_header.in
+++ b/util/grub.d/00_header.in
@@ -124,10 +124,24 @@ if [ -n "${GRUB_VIDEO_BACKEND}" ]; then
   insmod ${GRUB_VIDEO_BACKEND}
 EOF
 else
+# For EFI, use EFI video drivers only by default to avoid conflict between
+# GRUB Bochs/Cirrus and native EFI drivers. If GRUB_FORCE_EFI_ALL_VIDEO is
+# set/true then defer back to all_video even for EFI.
+if [ "${GRUB_FORCE_EFI_ALL_VIDEO}" = "1" ]; then
+    cat <<EOF
+  if [ x\$feature_all_video_module = xy ]; then
+EOF
+else # GRUB_FORCE_EFI_ALL_VIDEO is not set true
+    cat <<EOF
+  if [ x\$grub_platform = xefi ]; then
+    insmod efi_gop
+    insmod efi_uga
+  elif [ x\$feature_all_video_module = xy ]; then
+EOF
+fi # end GRUB_FORCE_EFI_ALL_VIDEO
 # If all_video.mod isn't available load all modules available
 # with versions prior to introduction of all_video.mod
 cat <<EOF
-  if [ x\$feature_all_video_module = xy ]; then
     insmod all_video
   else
     insmod efi_gop
-- 
2.43.0


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