linux-kernel - Re: [PATCH] pata_isapnp: Don't use invalid I/O ports

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Message-Id: <201309132344.27778.linux@rainbow-software.org>
Date:	Fri, 13 Sep 2013 23:44:27 +0200
From:	Ondrej Zary <linux@...nbow-software.org>
To:	linux-ide@...r.kernel.org
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] pata_isapnp: Don't use invalid I/O ports

On Friday 13 September 2013 20:54:37 Ondrej Zary wrote:
> On Thursday 12 September 2013 23:01:29 Ondrej Zary wrote:
> > The test for 2nd I/O port validity is broken (reversed):
> > On devices with no control port, the driver attempts to use invalid port
> > 0, resulting in logs full of bad_io_access errors.
> > On devices with control port, the driver does not use it.
> >
> > Signed-off-by: Ondrej Zary <linux@...nbow-software.org>
> > ---
> >  drivers/ata/pata_isapnp.c |    2 +-
> >  1 files changed, 1 insertions(+), 1 deletions(-)
> >
> > diff --git a/drivers/ata/pata_isapnp.c b/drivers/ata/pata_isapnp.c
> > index 4bceb88..b33d1f9 100644
> > --- a/drivers/ata/pata_isapnp.c
> > +++ b/drivers/ata/pata_isapnp.c
> > @@ -78,7 +78,7 @@ static int isapnp_init_one(struct pnp_dev *idev, const
> > struct pnp_device_id *dev
> >
> >  	ap->ioaddr.cmd_addr = cmd_addr;
> >
> > -	if (pnp_port_valid(idev, 1) == 0) {
> > +	if (pnp_port_valid(idev, 1)) {
> >  		ctl_addr = devm_ioport_map(&idev->dev,
> >  					   pnp_port_start(idev, 1), 1);
> >  		ap->ioaddr.altstatus_addr = ctl_addr;
>
> With this patch, the ATA port works fine if there is a device connected to
> it. However, it takes ages to boot if there are no devices connected. Looks
> like the driver retries IDENTIFY command for both slave and master drives
> in a hope that the devices are there.
>
> log:
>
> [    7.692344] pata_isapnp 01:01.02: [io  0x01e8-0x01ef]
> [    7.692474] pata_isapnp 01:01.02: [io  0x0168-0x016f]
> [    7.692644] pata_isapnp 01:01.02: [irq 10]
> [    7.695012] pata_isapnp 01:01.02: activated
> [    7.751153] scsi2 : pata_isapnp
> [    7.751781] ata3: PATA max PIO0 cmd 0x168 ctl 0x0 irq 10
> [   12.751446] ata3.01: qc timeout (cmd 0xec)
> [   12.751571] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
> [   22.752270] ata3.01: qc timeout (cmd 0xec)
> [   22.752396] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
> [   52.754737] ata3.01: qc timeout (cmd 0xec)
> [   52.754861] ata3.01: failed to IDENTIFY (I/O error, err_mask=0x5)
> [   57.755149] ata3.00: qc timeout (cmd 0xec)
> [   57.755275] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x5)
> [   67.755974] ata3.00: qc timeout (cmd 0xec)
> [   67.756099] ata3.00: failed to IDENTIFY (I/O error, err_mask=0x5)

This is caused by skipping ata_sff_softreset() when ap->ioaddr.ctl_addr is
unset so ata_devchk() is never called. This patch seems to fix the problem.
Is it OK or can it cause more problems?

--- a/drivers/ata/libata-sff.c
+++ b/drivers/ata/libata-sff.c
@@ -2008,13 +2008,15 @@ static int ata_bus_softreset(struct ata_port *ap, unsigned int devmask,
 
 	DPRINTK("ata%u: bus reset via SRST\n", ap->print_id);
 
-	/* software reset.  causes dev0 to be selected */
-	iowrite8(ap->ctl, ioaddr->ctl_addr);
-	udelay(20);	/* FIXME: flush */
-	iowrite8(ap->ctl | ATA_SRST, ioaddr->ctl_addr);
-	udelay(20);	/* FIXME: flush */
-	iowrite8(ap->ctl, ioaddr->ctl_addr);
-	ap->last_ctl = ap->ctl;
+	if (ap->ioaddr.ctl_addr) {
+		/* software reset.  causes dev0 to be selected */
+		iowrite8(ap->ctl, ioaddr->ctl_addr);
+		udelay(20);	/* FIXME: flush */
+		iowrite8(ap->ctl | ATA_SRST, ioaddr->ctl_addr);
+		udelay(20);	/* FIXME: flush */
+		iowrite8(ap->ctl, ioaddr->ctl_addr);
+		ap->last_ctl = ap->ctl;
+	}
 
 	/* wait the port to become ready */
 	return ata_sff_wait_after_reset(&ap->link, devmask, deadline);
@@ -2215,10 +2217,6 @@ void ata_sff_error_handler(struct ata_port *ap)
 
 	spin_unlock_irqrestore(ap->lock, flags);
 
-	/* ignore ata_sff_softreset if ctl isn't accessible */
-	if (softreset == ata_sff_softreset && !ap->ioaddr.ctl_addr)
-		softreset = NULL;
-
 	/* ignore built-in hardresets if SCR access is not available */
 	if ((hardreset == sata_std_hardreset ||
 	     hardreset == sata_sff_hardreset) && !sata_scr_valid(&ap->link))
-- 
Ondrej Zary
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