On Wed, 2 Dec 2009, David Miller wrote:
...
>
> Can you explain why the esp_slave_configure() part of your patch is
> necessary?
>
> > Index: linux-2.6.31/drivers/scsi/esp_scsi.c
> > ===================================================================
> > --- linux-2.6.31.orig/drivers/scsi/esp_scsi.c 2009-11-23 12:52:45.000000000 +1100
> > +++ linux-2.6.31/drivers/scsi/esp_scsi.c 2009-11-23 12:53:30.000000000 +1100
> > @@ -2405,12 +2405,6 @@ static int esp_slave_configure(struct sc
> > struct esp_target_data *tp = &esp->target[dev->id];
> > int goal_tags, queue_depth;
> >
> > - if (esp->flags & ESP_FLAG_DISABLE_SYNC) {
> > - /* Bypass async domain validation */
> > - dev->ppr = 0;
> > - dev->sdtr = 0;
> > - }
> > -
> > goal_tags = 0;
> >
> > if (dev->tagged_supported) {
> > @@ -2433,6 +2427,11 @@ static int esp_slave_configure(struct sc
> > }
> > tp->flags |= ESP_TGT_DISCONNECT;
> >
> > + if (esp->flags & ESP_FLAG_DISABLE_SYNC) {
> > + dev->wdtr = spi_support_wide(dev->sdev_target) = 0;
> > + dev->sdtr = spi_support_sync(dev->sdev_target) = 0;
> > + }
> > +
> > if (!spi_initial_dv(dev->sdev_target))
> > spi_dv_device(dev);
> >
The aim is that domain validation will not test for sync when we know it
can't work (in PIO mode). This is the result:
mac_esp: using PIO for controller 0
esp: esp0, regs[50f18000:(null)] irq[19]
esp: esp0 is a ESP236, 25 MHz (ccf=5), SCSI ID 7
scsi0 : esp
scsi 0:0:6:0: Direct-Access QUANTUM LPS540S 590S PQ: 0 ANSI: 2 CCS
target0:0:6: Beginning Domain Validation
target0:0:6: Ending Domain Validation
sd 0:0:6:0: [sda] 1057616 512-byte logical blocks: (541 MB/516 MiB)
sd 0:0:6:0: [sda] Write Protect is off
sd 0:0:6:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Whereas, without the esp_slave_configure() code, I get this:
scsi0 : esp
scsi 0:0:6:0: Direct-Access QUANTUM LPS540S 590S PQ: 0 ANSI: 2 CCS
target0:0:6: Beginning Domain Validation
target0:0:6: asynchronous
mac_esp: FIFO is empty (sreg 81)
esp: esp0: DMA length is zero!
esp: esp0: cur adr[010eb082] len[00000000]
target0:0:6: Domain Validation detected failure, dropping back
target0:0:6: asynchronous
mac_esp: FIFO is empty (sreg 81)
esp: esp0: DMA length is zero!
esp: esp0: cur adr[010eb082] len[00000000]
target0:0:6: Domain Validation detected failure, dropping back
target0:0:6: asynchronous
mac_esp: FIFO is empty (sreg 81)
esp: esp0: DMA length is zero!
esp: esp0: cur adr[010eb082] len[00000000]
target0:0:6: Domain Validation detected failure, dropping back
target0:0:6: asynchronous
mac_esp: FIFO is empty (sreg 81)
esp: esp0: DMA length is zero!
esp: esp0: cur adr[010eb082] len[00000000]
target0:0:6: Domain Validation detected failure, dropping back
target0:0:6: asynchronous
mac_esp: FIFO is empty (sreg 81)
esp: esp0: DMA length is zero!
esp: esp0: cur adr[010eb082] len[00000000]
target0:0:6: Domain Validation Failure, dropping back to Asynchronous
target0:0:6: Domain Validation skipping write tests
target0:0:6: Ending Domain Validation
sd 0:0:6:0: [sda] 1057616 512-byte logical blocks: (541 MB/516 MiB)
sd 0:0:6:0: [sda] Write Protect is off
sd 0:0:6:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
Which takes longer but gives the same result. The CDROM drive is worse
however:
scsi0 : esp
scsi 0:0:4:0: CD-ROM TOSHIBA CD-ROM XM-5401TA 1036 PQ: 0 ANSI: 2
target0:0:4: Beginning Domain Validation
target0:0:4: asynchronous
mac_esp: FIFO is empty (sreg 01)
esp: esp0: Aborting command [010dc940:12]
esp: esp0: Current command [010dc940:12]
esp: esp0: Active command [010dc940:12]
esp: esp0: Dumping command log
esp: esp0: ent[27] CMD val[01] sreg[87] seqreg[01] sreg2[00] ireg[10] ss[00] event[06]
esp: esp0: ent[28] CMD val[10] sreg[87] seqreg[01] sreg2[00] ireg[10] ss[00] event[06]
esp: esp0: ent[29] CMD val[12] sreg[87] seqreg[01] sreg2[00] ireg[08] ss[00] event[06]
esp: esp0: ent[30] EVENT val[0d] sreg[87] seqreg[01] sreg2[00] ireg[08] ss[00] event[06]
...
So the esp driver then retries the aborted command a few times, with
delays. Multiply those retries by the five domain validation iterations.
Then, IIRC, the CDROM finally gets offlined at the end of that slow
process.
I did a quick test, and this works too:
@@ -2405,12 +2405,6 @@ static int esp_slave_configure(struct sc
struct esp_target_data *tp = &esp->target[dev->id];
int goal_tags, queue_depth;
- if (esp->flags & ESP_FLAG_DISABLE_SYNC) {
- /* Bypass async domain validation */
- dev->ppr = 0;
- dev->sdtr = 0;
- }
-
goal_tags = 0;
if (dev->tagged_supported) {
@@ -2433,6 +2427,9 @@ static int esp_slave_configure(struct sc
}
tp->flags |= ESP_TGT_DISCONNECT;
+ if (esp->flags & ESP_FLAG_DISABLE_SYNC)
+ spi_support_sync(dev->sdev_target) = 0;
+
if (!spi_initial_dv(dev->sdev_target))
spi_dv_device(dev);
I will resubmit the patch like so if you wish. Or you could go ahead and
make the change.
Finn
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