[PATCH v2 06/17] hw/ide: name the retired IDENTIFY DEVICE words the device fills in

["Denis V. Lunev" <den@openvz.org>]

From: Denis V. Lunev <den@openvz.org>

Words 4, 5 and 20 have carried an "XXX: retired, remove ?" since the
device was written, and word 21 is labelled a cache size when it is a
buffer size. ATA-4 8.12.13 retired words 4 and 5, 8.12.17 retired words
20 and 21, and ATA-5 keeps all four that way.

Retired is not a reason to drop them. ATA-5 3.2.3.6 says a retired word
that is still used shall have "the meaning or functionality as described
in previous standards", and that is what these carry: ATA-1 9.9.3, 9.9.4
and 9.9.7 define the unformatted bytes per track and per sector and the
buffer type, and the ATA-1 IDENTIFY table gives word 21 as the buffer
size in 512 byte increments. Software old enough to read them gets what
it expects, so answer the question rather than leave it open.

Word 22 is obsolete rather than retired (ATA-4 8.12.18) and already
carries its ATA-1 9.9.8 name, so leave it alone.

Cc: John Snow <jsnow@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Cc: Philippe Mathieu-Daudé <philmd@oss.qualcomm.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
---
 hw/ide/core.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index befbab9486..292908fb1c 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -141,12 +141,12 @@ static void ide_identify(IDEState *s)
     /* Words 1, 3 and 6 describe the default translation (ATA-5 8.16.8) */
     put_le16(p + 1, s->cylinders);
     put_le16(p + 3, s->drive_heads);
-    put_le16(p + 4, 512 * s->drive_sectors); /* XXX: retired, remove ? */
-    put_le16(p + 5, 512); /* XXX: retired, remove ? */
+    put_le16(p + 4, 512 * s->drive_sectors); /* ATA-1 unformatted bytes/trk */
+    put_le16(p + 5, 512); /* ATA-1 unformatted bytes per sector */
     put_le16(p + 6, s->drive_sectors);
     padstr((char *)(p + 10), s->drive_serial_str, 20); /* serial number */
-    put_le16(p + 20, 3); /* XXX: retired, remove ? */
-    put_le16(p + 21, 512); /* cache size in sectors */
+    put_le16(p + 20, 3); /* ATA-1 buffer type: dual ported, read caching */
+    put_le16(p + 21, 512); /* ATA-1 buffer size in 512 byte increments */
     put_le16(p + 22, 4); /* ecc bytes */
     padstr((char *)(p + 23), s->version, 8); /* firmware version */
     padstr((char *)(p + 27), s->drive_model_str, 40); /* model */
-- 
2.53.0