Hello,

On Sunday 24 June 2007, Sergei Shtylyov wrote:

> >>>Index: b/drivers/ide/pci/sl82c105.c
> >>>===================================================================
> >>>--- a/drivers/ide/pci/sl82c105.c
> >>>+++ b/drivers/ide/pci/sl82c105.c
> >>>@@ -52,9 +52,10 @@
> >>>  * Convert a PIO mode and cycle time to the required on/off times
> >>>  * for the interface.  This has protection against runaway timings.
> >>>  */
> >>>-static unsigned int get_pio_timings(ide_pio_data_t *p)
> >>>+static unsigned int get_pio_timings(ide_drive_t *drive, ide_pio_data_t *p)
> >>> {
> >>>   unsigned int cmd_on, cmd_off;
> >>>+  u8 iordy = 0;
> 
> >>>   cmd_on  = (ide_pio_timings[p->pio_mode].active_time + 29) / 30;
> >>>   cmd_off = (p->cycle_time - 30 * cmd_on + 29) / 30;
> >>>@@ -65,7 +66,10 @@ static unsigned int get_pio_timings(ide_
> >>>   if (cmd_off == 0)
> >>>           cmd_off = 1;
> 
> >>>-  return (cmd_on - 1) << 8 | (cmd_off - 1) | (p->use_iordy ? 0x40 : 0x00);
> >>>+  if (p->pio_mode > 2 || ata_dev_has_iordy(drive->id))
> >>>+          iordy = 0x40;
> 
> >>    This logic, although mimicking the old one from 
> >> ide_get_best_pio_mode(), 
> >>is not quite correct. As have been noted before, when you set a PIO mode 
> >>using 
> 
>     It was actully correct enough, just superfluous -- it was me who was 
> incorrect, mistaking || for &&. :-<

After checking with ATA-2 spec I would prefer to leave extra p->pio_mode > 2
check (if ata_dev_has_iordy() fails device still _may_ support IORDY).

Fixed in "take 3" of the patch.

> >>Set Transfer Mode subcode of the Set Features command, you're always 
> >>selecting 
> >>the flow control mode, i.e. using IORDY. So, the last condition in this if 
> 
>     So, what actually would need fixing in *all* the drivers if one was 
> aiming 
> at ATA-1 compatibility is *not* issuing that subcommand to such drives...

I was actually thinking about a different way of fixing this:

- remove 0x08 bit from XFER_PIO_[0,6] defines and add new XFER_PIO_IORDY
  define (<linux/ata.h>)

- check for speed == XFER_PIO_[0,6] in ide-lib.c::ide_config_drive_speed()
  and pmac.c::pmac_ide_do_setfeature(), add XFER_PIO_IORDY if needed

This should be done together with fixing these host drivers that don't
handle IORDY properly.

> > Oh yes, I keep forgetting about it - some nice FIXME comment
> > in <linux/ata.h> would be of a great help. :-)
> 
>     Well, some drivers (like pdc202xx_*) don't do the IORDY thing right for 
> PIO modes < 3 as well...

Added to the existing IDE TODO at

        http://kernel.org/pub/linux/kernel/people/bart/pata-2.6/TODO

Patches adding/removing items are welcomed.

Patches fixing actual issues are welcomed even more.

> >>stmt should probably be the first, if not the sole one...
> 
> > Fixed, new patch below.
> 
> > [PATCH] ide: add ata_dev_has_iordy() helper (take 2)
> 
> > * Add ata_dev_has_iordy() helper and use it sl82c105 host driver.
> 
> > * Remove no longer needed ide_pio_data_t.use_iordy field.
> 
> > v2:
> > * Fix issues noticed by Sergei:
> >   - correct patch description
> >   - remove stale comment from ide_get_best_pio_mode()
> 
>     I meant something like changing use_iordy to IORDY but it's good as is 
> now...

Corrected in "take 3".

[PATCH] ide: add ata_dev_has_iordy() helper (take 3)

* Add ata_dev_has_iordy() helper and use it sl82c105 host driver.

* Remove no longer needed ide_pio_data_t.use_iordy field.

v2/v3:
* Fix issues noticed by Sergei:
  - correct patch description
  - fix comment in ide_get_best_pio_mode()

Signed-off-by: Bartlomiej Zolnierkiewicz <[EMAIL PROTECTED]>
Acked-by: Sergei Shtylyov <[EMAIL PROTECTED]>
---
 drivers/ide/ide-lib.c      |    7 +------
 drivers/ide/pci/sl82c105.c |   10 +++++++---
 include/linux/ide.h        |    6 +++++-
 3 files changed, 13 insertions(+), 10 deletions(-)

Index: b/drivers/ide/ide-lib.c
===================================================================
--- a/drivers/ide/ide-lib.c
+++ b/drivers/ide/ide-lib.c
@@ -267,18 +267,15 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
 {
        int pio_mode;
        int cycle_time = 0;
-       int use_iordy = 0;
        struct hd_driveid* id = drive->id;
        int overridden  = 0;
 
        if (mode_wanted != 255) {
                pio_mode = mode_wanted;
-               use_iordy = (pio_mode > 2);
        } else if (!drive->id) {
                pio_mode = 0;
        } else if ((pio_mode = ide_scan_pio_blacklist(id->model)) != -1) {
                printk(KERN_INFO "%s: is on PIO blacklist\n", drive->name);
-               use_iordy = (pio_mode > 2);
        } else {
                pio_mode = id->tPIO;
                if (pio_mode > 2) {     /* 2 is maximum allowed tPIO value */
@@ -286,8 +283,7 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
                        overridden = 1;
                }
                if (id->field_valid & 2) {        /* drive implements ATA2? */
-                       if (id->capability & 8) { /* drive supports use_iordy? 
*/
-                               use_iordy = 1;
+                       if (id->capability & 8) { /* IORDY supported? */
                                cycle_time = id->eide_pio_iordy;
                                if (id->eide_pio_modes & 7) {
                                        overridden = 0;
@@ -325,7 +321,6 @@ u8 ide_get_best_pio_mode (ide_drive_t *d
        if (d) {
                d->pio_mode = pio_mode;
                d->cycle_time = cycle_time ? cycle_time : 
ide_pio_timings[pio_mode].cycle_time;
-               d->use_iordy = use_iordy;
        }
        return pio_mode;
 }
Index: b/drivers/ide/pci/sl82c105.c
===================================================================
--- a/drivers/ide/pci/sl82c105.c
+++ b/drivers/ide/pci/sl82c105.c
@@ -52,9 +52,10 @@
  * Convert a PIO mode and cycle time to the required on/off times
  * for the interface.  This has protection against runaway timings.
  */
-static unsigned int get_pio_timings(ide_pio_data_t *p)
+static unsigned int get_pio_timings(ide_drive_t *drive, ide_pio_data_t *p)
 {
        unsigned int cmd_on, cmd_off;
+       u8 iordy = 0;
 
        cmd_on  = (ide_pio_timings[p->pio_mode].active_time + 29) / 30;
        cmd_off = (p->cycle_time - 30 * cmd_on + 29) / 30;
@@ -65,7 +66,10 @@ static unsigned int get_pio_timings(ide_
        if (cmd_off == 0)
                cmd_off = 1;
 
-       return (cmd_on - 1) << 8 | (cmd_off - 1) | (p->use_iordy ? 0x40 : 0x00);
+       if (p->pio_mode > 2 || ata_dev_has_iordy(drive->id))
+               iordy = 0x40;
+
+       return (cmd_on - 1) << 8 | (cmd_off - 1) | iordy;
 }
 
 /*
@@ -82,7 +86,7 @@ static u8 sl82c105_tune_pio(ide_drive_t 
 
        pio = ide_get_best_pio_mode(drive, pio, 5, &p);
 
-       drv_ctrl = get_pio_timings(&p);
+       drv_ctrl = get_pio_timings(drive, &p);
 
        /*
         * Store the PIO timings so that we can restore them
Index: b/include/linux/ide.h
===================================================================
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -1363,6 +1363,11 @@ extern void ide_toggle_bounce(ide_drive_
 extern int ide_set_xfer_rate(ide_drive_t *drive, u8 rate);
 int ide_use_fast_pio(ide_drive_t *);
 
+static inline int ata_dev_has_iordy(struct hd_driveid *id)
+{
+       return ((id->field_valid & 2) && (id->capability & 8)) ? 1 : 0;
+}
+
 u8 ide_dump_status(ide_drive_t *, const char *, u8);
 
 typedef struct ide_pio_timings_s {
@@ -1374,7 +1379,6 @@ typedef struct ide_pio_timings_s {
 
 typedef struct ide_pio_data_s {
        u8 pio_mode;
-       u8 use_iordy;
        unsigned int cycle_time;
 } ide_pio_data_t;
 
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