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ide: don't tamper with the device register

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In real ISA operation, register writes go out to an entire bus channel
and all listening devices receive the write. The devices do not toggle
the DEV bit based on their own configuration, nor does the HBA
intermediate or tamper with that value.

The reality of the matter is that DEV0/DEV1 accordingly will react to
command register writes based on whether or not the device was selected.

This does not fix a known bug, but it makes the code slightly simpler
and more obvious.

Signed-off-by: John Snow <jsnow@redhat.com>
This commit is contained in:
John Snow 2020-07-24 01:22:55 -04:00
parent 98d9891223
commit f14bc040b0
1 changed files with 2 additions and 2 deletions
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4
hw/ide/core.c
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@ -1297,8 +1297,8 @@ void ide_ioport_write(void *opaque, uint32_t addr, uint32_t val)
break;
case ATA_IOPORT_WR_DEVICE_HEAD:
/* FIXME: HOB readback uses bit 7 */
bus->ifs[0].select = (val & ~0x10) | 0xa0;
bus->ifs[1].select = (val | 0x10) | 0xa0;
bus->ifs[0].select = val | 0xa0;
bus->ifs[1].select = val | 0xa0;
/* select drive */
bus->unit = (val >> 4) & 1;
break;