[MULTIBOOT2,DOC,v3,05/13] multiboot2: Clarify meaning of information request header tag
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Message ID 1481064781-16949-6-git-send-email-daniel.kiper@oracle.com
State New, archived
Headers show

Commit Message

Daniel Kiper Dec. 6, 2016, 10:52 p.m. UTC
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
---
v2 - suggestions/fixes:
   - rephrase some sentences
     (suggested by Andrew Cooper),
   - add missing the articles
     (suggested by Andrew Cooper).
---
 doc/multiboot.texi |   20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

Patch
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diff --git a/doc/multiboot.texi b/doc/multiboot.texi
index a9cba9b..4f838f0 100644
--- a/doc/multiboot.texi
+++ b/doc/multiboot.texi
@@ -437,15 +437,19 @@  u32[n]  | mbi_tag_types     |
 @end group
 @end example
 
-@samp{mbi_tag_types} is an array of u32 each one representing an information
-request
-If this tag is present and @samp{optional} is set to @samp{0} information
-conveyed by requested tag types must be present. If bootloader is unable
-to supply this information it must fail with an error
+@samp{mbi_tag_types} is an array of u32's, each one representing an information request.
 
-Note: it doesn't garantee that any tags of type @samp{mbi_tag_types} will
-actually be present. E.g. on a videoless system even if you requested tag
-@samp{8} no tags of type @samp{8} will be present in mbi.
+If this tag is present and @samp{optional} is set to @samp{0}, the bootloader must
+support the requested tag and be able to provide relevant information to the image
+if it is available. If the bootloader does not understand the meaning of the requested
+tag it must fail with an error. However, if it supports a given tag but the information
+conveyed by it is not available the bootloader does not provide the requested tag in
+the Multiboot2 information structure and passes control to the loaded image as usual.
+
+Note: The above means that there is no guarantee that any tags of type @samp{mbi_tag_types}
+will actually be present. E.g. on a videoless system even if you requested tag @samp{8}
+and the bootloader supports it, no tags of type @samp{8} will be present in the Multiboot2
+information structure.
 
 
 @node Address header tag