Re: [PATCH] libata: skip reset on bus not a device

[Tejun Heo <htejun@gmail.com>]

Hello, Joe Jin.

Joe Jin wrote:
> On my pc(Dell OptiPlex GX620), while boot up it by 2.6.18, the next
> info always report:
> ===========================================
> ata2: port is slow to respond, please be patient
> ata2: port failed to respond (30 secs)
> ata2: SRST failed (status 0xFF)
> ata2: SRST failed (err_mask=0x100)
> ata2: softreset failed, retrying in 5 secs
> ata2: SRST failed (status 0xFF)
> ata2: SRST failed (err_mask=0x100)
> ata2: softreset failed, retrying in 5 secs
> ata2: SRST failed (status 0xFF)
> ata2: SRST failed (err_mask=0x100)
> ata2: reset failed, giving up
> ===========================================

I see.

> 00:1f.1 IDE interface: Intel Corporation 82801G (ICH7 Family) IDE
> Controller (rev 01) (prog-if 8a [Master SecP PriP])
>        Subsystem: Dell: Unknown device 01ad
>        Flags: bus master, medium devsel, latency 0, IRQ 169
>        I/O ports at <ignored>
>        I/O ports at <ignored>
>        I/O ports at <ignored>
>        I/O ports at <ignored>
>        I/O ports at ffa0 [size=16]
> 00: 86 80 df 27 05 00 88 02 01 8a 01 01 00 00 00 00
> 10: f1 01 00 00 f5 03 00 00 71 01 00 00 75 03 00 00
> 20: a1 ff 00 00 00 00 00 00 00 00 00 00 28 10 ad 01
> 30: 00 00 00 00 00 00 00 00 00 00 00 00 0b 01 00 00
>
> 00:1f.2 IDE interface: Intel Corporation 82801GB/GR/GH (ICH7 Family)
> Serial ATA Storage Controller IDE (rev 01) (prog-if 8f [Master SecP
> SecO PriP PriO])
>        Subsystem: Dell: Unknown device 01ad
>        Flags: bus master, 66Mhz, medium devsel, latency 0, IRQ 217
>        I/O ports at fe00 [size=8]
>        I/O ports at fe10 [size=4]
>        I/O ports at fe20 [size=8]
>        I/O ports at fe30 [size=4]
>        I/O ports at fea0 [size=16]
>        Capabilities: <available only to root>
> 00: 86 80 c0 27 07 00 b0 02 01 8f 01 01 00 00 00 00
> 10: 01 fe 00 00 11 fe 00 00 21 fe 00 00 31 fe 00 00
> 20: a1 fe 00 00 00 00 00 00 00 00 00 00 28 10 ad 01
> 30: 00 00 00 00 70 00 00 00 00 00 00 00 05 03 00 00

Can you post the result of the following command.

# lspci -nvvvxxx -s 00:1f.

> through traced the code, and found which caused it:
> at scsi_eh_[port_no] kernel thread, it should reset the bus, before 
> reset it,
> it never check it if have a device. if it should skip it?
> thanks

Hmmm... Not really.  The controller shouldn't report BSY for empty 
channel.  There's a notable exception where PATA pins aren't properly 
pulled resulting in 0xff status on empty channels.  IDE handles the case 
specially but libata doesn't yet.  Can you try the attached patch?

--
tejun

diff --git a/drivers/scsi/libata-core.c b/drivers/scsi/libata-core.c
index 427b73a..c8a1bc6 100644
--- a/drivers/scsi/libata-core.c
+++ b/drivers/scsi/libata-core.c
@@ -2271,11 +2271,14 @@ static inline void ata_tf_to_host(struct
  *	Sleep until ATA Status register bit BSY clears,
  *	or a timeout occurs.
  *
- *	LOCKING: None.
+ *	LOCKING:
+ *	Kernel thread context (may sleep).
+ *
+ *	RETURNS:
+ *	0 on success, -errno otherwise.
  */
-
-unsigned int ata_busy_sleep (struct ata_port *ap,
-			     unsigned long tmout_pat, unsigned long tmout)
+int ata_busy_sleep(struct ata_port *ap,
+		   unsigned long tmout_pat, unsigned long tmout)
 {
 	unsigned long timer_start, timeout;
 	u8 status;
@@ -2283,25 +2286,30 @@ unsigned int ata_busy_sleep (struct ata_
 	status = ata_busy_wait(ap, ATA_BUSY, 300);
 	timer_start = jiffies;
 	timeout = timer_start + tmout_pat;
-	while ((status & ATA_BUSY) && (time_before(jiffies, timeout))) {
+	while (status != 0xff && (status & ATA_BUSY) &&
+	       time_before(jiffies, timeout)) {
 		msleep(50);
 		status = ata_busy_wait(ap, ATA_BUSY, 3);
 	}
 
-	if (status & ATA_BUSY)
+	if (status != 0xff && (status & ATA_BUSY))
 		ata_port_printk(ap, KERN_WARNING,
 				"port is slow to respond, please be patient\n");
 
 	timeout = timer_start + tmout;
-	while ((status & ATA_BUSY) && (time_before(jiffies, timeout))) {
+	while (status != 0xff && (status & ATA_BUSY) &&
+	       time_before(jiffies, timeout)) {
 		msleep(50);
 		status = ata_chk_status(ap);
 	}
 
+	if (status == 0xff)
+		return -ENODEV;
+
 	if (status & ATA_BUSY) {
 		ata_port_printk(ap, KERN_ERR, "port failed to respond "
 				"(%lu secs)\n", tmout / HZ);
-		return 1;
+		return -EBUSY;
 	}
 
 	return 0;
diff --git a/include/linux/libata.h b/include/linux/libata.h
index 66c3100..eb7d90f 100644
--- a/include/linux/libata.h
+++ b/include/linux/libata.h
@@ -702,9 +702,8 @@ extern int ata_host_set_suspend(struct a
 				pm_message_t mesg);
 extern void ata_host_set_resume(struct ata_host_set *host_set);
 extern int ata_ratelimit(void);
-extern unsigned int ata_busy_sleep(struct ata_port *ap,
-				   unsigned long timeout_pat,
-				   unsigned long timeout);
+extern int ata_busy_sleep(struct ata_port *ap,
+			  unsigned long timeout_pat, unsigned long timeout);
 extern void ata_port_queue_task(struct ata_port *ap, void (*fn)(void *),
 				void *data, unsigned long delay);
 extern u32 ata_wait_register(void __iomem *reg, u32 mask, u32 val,
@@ -1019,7 +1018,7 @@ static inline u8 ata_busy_wait(struct at
 		udelay(10);
 		status = ata_chk_status(ap);
 		max--;
-	} while ((status & bits) && (max > 0));
+	} while (status != 0xff && (status & bits) && (max > 0));
 
 	return status;
 }
@@ -1040,7 +1039,7 @@ static inline u8 ata_wait_idle(struct at
 {
 	u8 status = ata_busy_wait(ap, ATA_BUSY | ATA_DRQ, 1000);
 
-	if (status & (ATA_BUSY | ATA_DRQ)) {
+	if (status != 0xff && (status & (ATA_BUSY | ATA_DRQ))) {
 		unsigned long l = ap->ioaddr.status_addr;
 		if (ata_msg_warn(ap))
 			printk(KERN_WARNING "ATA: abnormal status 0x%X on port 0x%lX\n",