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| author | David Pursell <dpursell@google.com> | 2016-12-21 15:42:23 -0800 |
|---|---|---|
| committer | David Pursell <dpursell@google.com> | 2016-12-21 15:59:50 -0800 |
| commit | c56d63e59d76062e77546a742374cfac80c56c43 (patch) | |
| tree | 735518dfa471dbe22671213d36c1b332a626ef24 /fastboot | |
| parent | 3d6d5b101aa90115c50c4656603983d72019351f (diff) | |
| download | system_core-c56d63e59d76062e77546a742374cfac80c56c43.tar.gz system_core-c56d63e59d76062e77546a742374cfac80c56c43.tar.bz2 system_core-c56d63e59d76062e77546a742374cfac80c56c43.zip | |
fastboot: update getvar documentation.
The protocol doc states that calling `fastboot getvar` for an unknown
variable should return an empty OKAY message, but in reality modern
devices return a FAIL response in this case (tested with marlin and
shamu).
Additionally, some A/B logic in fastboot expects a FAIL response for
unknown variables in order to function properly.
This CL changes the documentation to match reality.
Bug: http://b/33756193
Test: none
Change-Id: I41f7c80585be73e60ca0ac216787596c4d60a1d5
Diffstat (limited to 'fastboot')
| -rw-r--r-- | fastboot/fastboot_protocol.txt | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/fastboot/fastboot_protocol.txt b/fastboot/fastboot_protocol.txt index 2801703c8..b12e42038 100644 --- a/fastboot/fastboot_protocol.txt +++ b/fastboot/fastboot_protocol.txt @@ -78,7 +78,7 @@ Client: "OKAY0.4" return version "0.4" Host: "getvar:nonexistant" request some undefined variable -Client: "OKAY" return value "" +Client: "FAILUnknown variable" getvar failure; see getvar details below Host: "download:00001234" request to send 0x1234 bytes of data @@ -113,7 +113,14 @@ Command Reference "getvar:%s" Read a config/version variable from the bootloader. The variable contents will be returned after the - OKAY response. + OKAY response. If the variable is unknown, the bootloader + should return a FAIL response, optionally with an error + message. + + Previous versions of this document indicated that getvar + should return an empty OKAY response for unknown + variables, so older devices might exhibit this behavior, + but new implementations should return FAIL instead. "download:%08x" Write data to memory which will be later used by "boot", "ramdisk", "flash", etc. The client @@ -215,7 +222,7 @@ Device FB01 Host [0x00][0x00][0x00][0x00][0x00][0x00][0x00][0x0E]getvar:version Device [0x00][0x00][0x00][0x00][0x00][0x00][0x00][0x07]OKAY0.4 Host [0x00][0x00][0x00][0x00][0x00][0x00][0x00][0x0B]getvar:none -Device [0x00][0x00][0x00][0x00][0x00][0x00][0x00][0x04]OKAY +Device [0x00][0x00][0x00][0x00][0x00][0x00][0x00][0x14]FAILUnknown variable Host <disconnect> @@ -364,10 +371,10 @@ ID Flags SeqH SeqL Data ID Flags SeqH SeqL Data 0x03 0x00 0x00 0x01 0x03 0x00 0x00 0x02 0x03 0x00 0x00 0x02 OKAY0.4 -0x03 0x00 0x00 0x03 getvar:foo +0x03 0x00 0x00 0x03 getvar:none 0x03 0x00 0x00 0x03 0x03 0x00 0x00 0x04 - 0x03 0x00 0x00 0x04 OKAY + 0x03 0x00 0x00 0x04 FAILUnknown var ---------------------------------------------------------------------- [fastboot "INFO" responses, S = 0x0000] |