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scsi-disk: add SCSI_DISK_QUIRK_MODE_SENSE_ROM_USE_DBD quirk for Macintosh

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During SCSI bus enumeration A/UX sends a MODE SENSE command to the CDROM with
the DBD bit unset and expects the response to include a block descriptor. As per
the latest SCSI documentation, QEMU currently force-disables the block
descriptor for CDROM devices but the A/UX driver expects the requested block
descriptor to be returned.

If the block descriptor is not returned in the response then A/UX becomes
confused, since the block descriptor returned in the MODE SENSE response is
used to generate a subsequent MODE SELECT command which is then invalid.

Add a new SCSI_DISK_QUIRK_MODE_SENSE_ROM_USE_DBD quirk to allow this behaviour
to be enabled as required. Note that an additional workaround is required for
the previous SCSI_DISK_QUIRK_MODE_PAGE_APPLE_VENDOR quirk which must never
return a block descriptor even though the DBD bit is left unset.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Message-Id: <20220622105314.802852-5-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Mark Cave-Ayland 2022-06-22 11:53:04 +01:00 committed by Paolo Bonzini
parent f358241029
commit f43c2b94cd
2 changed files with 24 additions and 4 deletions
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27
hw/scsi/scsi-disk.c
View File

@ -1279,10 +1279,27 @@ static int scsi_disk_emulate_mode_sense(SCSIDiskReq *r, uint8_t *outbuf)
dev_specific_param |= 0x80; /* Readonly. */
}
} else {
/* MMC prescribes that CD/DVD drives have no block descriptors,
* and defines no device-specific parameter. */
dev_specific_param = 0x00;
dbd = true;
if (s->quirks & (1 << SCSI_DISK_QUIRK_MODE_SENSE_ROM_USE_DBD)) {
/* Use DBD from the request... */
dev_specific_param = 0x00;
/*
* ... unless we receive a request for MODE_PAGE_APPLE_VENDOR
* which should never return a block descriptor even though DBD is
* not set, otherwise CDROM detection fails in MacOS
*/
if (s->quirks & (1 << SCSI_DISK_QUIRK_MODE_PAGE_APPLE_VENDOR) &&
page == MODE_PAGE_APPLE_VENDOR) {
dbd = true;
}
} else {
/*
* MMC prescribes that CD/DVD drives have no block descriptors,
* and defines no device-specific parameter.
*/
dev_specific_param = 0x00;
dbd = true;
}
}
if (r->req.cmd.buf[0] == MODE_SENSE) {
@ -3102,6 +3119,8 @@ static Property scsi_cd_properties[] = {
5),
DEFINE_PROP_BIT("quirk_mode_page_apple_vendor", SCSIDiskState, quirks,
SCSI_DISK_QUIRK_MODE_PAGE_APPLE_VENDOR, 0),
DEFINE_PROP_BIT("quirk_mode_sense_rom_use_dbd", SCSIDiskState, quirks,
SCSI_DISK_QUIRK_MODE_SENSE_ROM_USE_DBD, 0),
DEFINE_PROP_END_OF_LIST(),
};

1
include/hw/scsi/scsi.h
View File

@ -228,5 +228,6 @@ extern const SCSIReqOps scsi_generic_req_ops;
/* scsi-disk.c */
#define SCSI_DISK_QUIRK_MODE_PAGE_APPLE_VENDOR 0
#define SCSI_DISK_QUIRK_MODE_SENSE_ROM_USE_DBD 1
#endif