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authorKonstantin Aladyshev <aladyshev22@gmail.com>2022-03-27 20:11:11 +0300
committerKonstantin Aladyshev <aladyshev22@gmail.com>2022-03-27 20:11:11 +0300
commite1e4e92633fba1bdc3212babe06e48fce3aaa479 (patch)
treea6c32034fdb81bb0b8298b27d5fbc55d3f0af2a9
parent7e55f3078442ba83ef669e018645128b29daae17 (diff)
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Add information about DEBUG max string length
Signed-off-by: Konstantin Aladyshev <aladyshev22@gmail.com>
-rw-r--r--Lessons/Lesson_41/README.md13
1 files changed, 11 insertions, 2 deletions
diff --git a/Lessons/Lesson_41/README.md b/Lessons/Lesson_41/README.md
index 6b68e92..4eb3684 100644
--- a/Lessons/Lesson_41/README.md
+++ b/Lessons/Lesson_41/README.md
@@ -469,8 +469,17 @@ DiscoverPeimsAndOrderWithApriori(): Found 0x7 PEI FFS files in the 0th FV
It is much easier to read now!
+# Max string length in `DEBUG` output
+There is a limitation to the maximum string length that can be outputed with a `DEBUG` statement.
+https://github.com/tianocore/edk2/blob/master/OvmfPkg/Library/PlatformDebugLibIoPort/DebugLib.c:
+```
+#define MAX_DEBUG_MESSAGE_LENGTH 0x100
+```
+If the printed sting is longer than this limit, the output would be truncated to the first `MAX_DEBUG_MESSAGE_LENGTH` symbols. Most probably you would notice this by the fact that `\n` symbol at the end of the string would be lost, and the next printed string wouldn't start from the new line.
-
-
+In this case you might consider increasing the aforementioned limit, for this change the value above and recompile OVMF:
+```
+build --platform=OvmfPkg/OvmfPkgX64.dsc --arch=X64 --buildtarget=DEBUG --tagname=GCC5
+```