[PATCH] ide: Set IDENTIFY word 93 to 0 on SATA drives

[Pedro Falcato <pfalcato@suse.de>]

According to the ATA Command Set specification (and the SATA specification
too), SATA drives are supposed to set word 93 (which for PATA holds hardware
reset results) to 0. As such, clear it when ncq_queues > 0 (which is only true
for SATA drives).

Doing so fixes a quirk in Linux where it thinks the AHCI QEMU drive is PATA
over a SATA bridge, and thus limits maximum transfer sizes for individual IOs
with a:
[    1.632121] ata1.00: applying bridge limits

While at it, bump the device's firmware revision for IDENTIFY. This makes it
so Linux can avoid enabling a quirk for fixed QEMU releases.

Link: https://lore.kernel.org/linux-ide/20260303183337.1013474-1-pfalcato@suse.de/
Cc: qemu-stable@nongnu.org
Suggsted-by: Niklas Cassel <cassel@kernel.org>
Signed-off-by: Pedro Falcato <pfalcato@suse.de>
---
Note: I understand the version bump is vaguely controversial (particularly
 exposing the QEMU version in the string) but I don't have a much better
 idea. Logically, bumping it to 11.0 for stable releases doesn't make much
 sense.
 
 hw/ide/core.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/hw/ide/core.c b/hw/ide/core.c
index b45abf067b20..89f62f301e94 100644
--- a/hw/ide/core.c
+++ b/hw/ide/core.c
@@ -211,7 +211,15 @@ static void ide_identify(IDEState *s)
         put_le16(p + 87, (1 << 14) | 0);
     }
     put_le16(p + 88, 0x3f | (1 << 13)); /* udma5 set and supported */
-    put_le16(p + 93, 1 | (1 << 14) | 0x2000);
+    if (s->ncq_queues) {
+        /*
+         * This is SATA, which is required by the spec to return 0 for this
+         * field.
+         */
+        put_le16(p + 93, 0);
+    } else {
+        put_le16(p + 93, 1 | (1 << 14) | 0x2000);
+    }
     /* *(p + 100) := nb_sectors       -- see ide_identify_size */
     /* *(p + 101) := nb_sectors >> 16 -- see ide_identify_size */
     /* *(p + 102) := nb_sectors >> 32 -- see ide_identify_size */
@@ -2660,7 +2668,7 @@ int ide_init_drive(IDEState *s, IDEDevice *dev, IDEDriveKind kind, Error **errp)
     if (dev->version) {
         pstrcpy(s->version, sizeof(s->version), dev->version);
     } else {
-        pstrcpy(s->version, sizeof(s->version), qemu_hw_version());
+        pstrcpy(s->version, sizeof(s->version), "11.0");
     }
 
     ide_reset(s);
-- 
2.53.0