On 10/11/2014 16:52, Hannes Reinecke wrote: > After a reset ESP_TCHI should contain the unique ID > of the chip. This value will be overwritten with the > current tranfer count if the transfer count has > previously been set. > So we should always return the chip id if ESP_TCHI > has never been written to.
What if ESP_TCHI was written 0? Why should it return the chip id? Can you explain exactly what sequence of register reads/writes leads to the bug? Paolo > Signed-off-by: Hannes Reinecke <h...@suse.de> > --- > hw/scsi/esp.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/hw/scsi/esp.c b/hw/scsi/esp.c > index 5ab44d8..2caac1c 100644 > --- a/hw/scsi/esp.c > +++ b/hw/scsi/esp.c > @@ -364,7 +364,6 @@ void esp_hard_reset(ESPState *s) > { > memset(s->rregs, 0, ESP_REGS); > memset(s->wregs, 0, ESP_REGS); > - s->rregs[ESP_TCHI] = s->chip_id; > s->ti_size = 0; > s->ti_rptr = 0; > s->ti_wptr = 0; > @@ -422,6 +421,11 @@ uint64_t esp_reg_read(ESPState *s, uint32_t saddr) > esp_lower_irq(s); > > return old_val; > + case ESP_TCHI: > + /* Return the unique id if the value has never been written */ > + if (!s->wregs[ESP_TCHI]) { > + return s->chip_id; > + } > default: > break; > } >