libata: prefer hardreset
When both soft and hard resets are available, libata preferred
softreset till now. The logic behind it was to be softer to devices;
however, this doesn't really help much. Rationales for the change:
* BIOS may freeze lock certain things during boot and softreset can't
unlock those. This by itself is okay but during operation PHY event
or other error conditions can trigger hardreset and the device may
end up with different configuration.
For example, after a hardreset, previously unlockable HPA can be
unlocked resulting in different device size and thus revalidation
failure. Similar condition can occur during or after resume.
* Certain ATAPI devices require hardreset to recover after certain
error conditions. On PATA, this is done by issuing the DEVICE RESET
command. On SATA, COMRESET has equivalent effect. The problem is
that DEVICE RESET needs its own execution protocol.
For SFF controllers with bare TF access, it can be easily
implemented but more advanced controllers (e.g. ahci and sata_sil24)
require specialized implementations. Simply using hardreset solves
the problem nicely.
* COMRESET initialization sequence is the norm in SATA land and many
SATA devices don't work properly if only SRST is used. For example,
some PMPs behave this way and libata works around by always issuing
hardreset if the host supports PMP.
Like the above example, libata has developed a number of mechanisms
aiming to promote softreset to hardreset if softreset is not going
to work. This approach is time consuming and error prone.
Also, note that, dependingon how you read the specs, it could be
argued that PMP fan-out ports require COMRESET to start operation.
In fact, all the PMPs on the market except one don't work properly
if COMRESET is not issued to fan-out ports after PMP reset.
* COMRESET is an integral part of SATA connection and any working
device should be able to handle COMRESET properly. After all, it's
the way to signal hardreset during reboot. This is the most used
and recommended (at least by the ahci spec) method of resetting
devices.
So, this patch makes libata prefer hardreset over softreset by making
the following changes.
* Rename ATA_EH_RESET_MASK to ATA_EH_RESET and use it whereever
ATA_EH_{SOFT|HARD}RESET used to be used. ATA_EH_{SOFT|HARD}RESET is
now only used to tell prereset whether soft or hard reset will be
issued.
* Strip out now unneeded promote-to-hardreset logics from
ata_eh_reset(), ata_std_prereset(), sata_pmp_std_prereset() and
other places.
Signed-off-by: Tejun Heo <htejun@gmail.com>
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index a583032..f7cae64 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -1079,16 +1079,9 @@
spin_lock_irqsave(ap->lock, flags);
- /* Reset is represented by combination of actions and EHI
- * flags. Suck in all related bits before clearing eh_info to
- * avoid losing requested action.
- */
- if (action & ATA_EH_RESET_MASK) {
- ehc->i.action |= ehi->action & ATA_EH_RESET_MASK;
+ /* suck in and clear reset modifier */
+ if (action & ATA_EH_RESET) {
ehc->i.flags |= ehi->flags & ATA_EHI_RESET_MODIFIER_MASK;
-
- /* make sure all reset actions are cleared & clear EHI flags */
- action |= ATA_EH_RESET_MASK;
ehi->flags &= ~ATA_EHI_RESET_MODIFIER_MASK;
}
@@ -1117,11 +1110,9 @@
{
struct ata_eh_context *ehc = &link->eh_context;
- /* if reset is complete, clear all reset actions & reset modifier */
- if (action & ATA_EH_RESET_MASK) {
- action |= ATA_EH_RESET_MASK;
+ /* if reset is complete, clear reset modifier */
+ if (action & ATA_EH_RESET)
ehc->i.flags &= ~ATA_EHI_RESET_MODIFIER_MASK;
- }
ata_eh_clear_action(link, dev, &ehc->i, action);
}
@@ -1329,20 +1320,20 @@
if (serror & SERR_PERSISTENT) {
err_mask |= AC_ERR_ATA_BUS;
- action |= ATA_EH_HARDRESET;
+ action |= ATA_EH_RESET;
}
if (serror &
(SERR_DATA_RECOVERED | SERR_COMM_RECOVERED | SERR_DATA)) {
err_mask |= AC_ERR_ATA_BUS;
- action |= ATA_EH_SOFTRESET;
+ action |= ATA_EH_RESET;
}
if (serror & SERR_PROTOCOL) {
err_mask |= AC_ERR_HSM;
- action |= ATA_EH_SOFTRESET;
+ action |= ATA_EH_RESET;
}
if (serror & SERR_INTERNAL) {
err_mask |= AC_ERR_SYSTEM;
- action |= ATA_EH_HARDRESET;
+ action |= ATA_EH_RESET;
}
/* Determine whether a hotplug event has occurred. Both
@@ -1448,7 +1439,7 @@
if ((stat & (ATA_BUSY | ATA_DRQ | ATA_DRDY)) != ATA_DRDY) {
qc->err_mask |= AC_ERR_HSM;
- return ATA_EH_SOFTRESET;
+ return ATA_EH_RESET;
}
if (stat & (ATA_ERR | ATA_DF))
@@ -1484,7 +1475,7 @@
}
if (qc->err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT | AC_ERR_ATA_BUS))
- action |= ATA_EH_SOFTRESET;
+ action |= ATA_EH_RESET;
return action;
}
@@ -1685,7 +1676,7 @@
if (verdict & ATA_EH_SPDN_SPEED_DOWN) {
/* speed down SATA link speed if possible */
if (sata_down_spd_limit(link) == 0) {
- action |= ATA_EH_HARDRESET;
+ action |= ATA_EH_RESET;
goto done;
}
@@ -1705,7 +1696,7 @@
dev->spdn_cnt++;
if (ata_down_xfermask_limit(dev, sel) == 0) {
- action |= ATA_EH_SOFTRESET;
+ action |= ATA_EH_RESET;
goto done;
}
}
@@ -1719,7 +1710,7 @@
(dev->xfer_shift != ATA_SHIFT_PIO)) {
if (ata_down_xfermask_limit(dev, ATA_DNXFER_FORCE_PIO) == 0) {
dev->spdn_cnt = 0;
- action |= ATA_EH_SOFTRESET;
+ action |= ATA_EH_RESET;
goto done;
}
}
@@ -1764,9 +1755,9 @@
ehc->i.serror |= serror;
ata_eh_analyze_serror(link);
} else if (rc != -EOPNOTSUPP) {
- /* SError read failed, force hardreset and probing */
+ /* SError read failed, force reset and probing */
ata_ehi_schedule_probe(&ehc->i);
- ehc->i.action |= ATA_EH_HARDRESET;
+ ehc->i.action |= ATA_EH_RESET;
ehc->i.err_mask |= AC_ERR_OTHER;
}
@@ -1814,7 +1805,7 @@
/* enforce default EH actions */
if (ap->pflags & ATA_PFLAG_FROZEN ||
all_err_mask & (AC_ERR_HSM | AC_ERR_TIMEOUT))
- ehc->i.action |= ATA_EH_SOFTRESET;
+ ehc->i.action |= ATA_EH_RESET;
else if (((eflags & ATA_EFLAG_IS_IO) && all_err_mask) ||
(!(eflags & ATA_EFLAG_IS_IO) && (all_err_mask & ~AC_ERR_DEV)))
ehc->i.action |= ATA_EH_REVALIDATE;
@@ -2118,7 +2109,6 @@
int try = 0;
struct ata_device *dev;
unsigned long deadline, now;
- unsigned int tmp_action;
ata_reset_fn_t reset;
unsigned long flags;
u32 sstatus;
@@ -2129,7 +2119,7 @@
ap->pflags |= ATA_PFLAG_RESETTING;
spin_unlock_irqrestore(ap->lock, flags);
- ata_eh_about_to_do(link, NULL, ehc->i.action & ATA_EH_RESET_MASK);
+ ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
ata_link_for_each_dev(dev, link) {
/* If we issue an SRST then an ATA drive (not ATAPI)
@@ -2159,17 +2149,15 @@
goto done;
}
- /* Determine which reset to use and record in ehc->i.action.
- * prereset() may examine and modify it.
- */
- if (softreset && (!hardreset || (!(lflags & ATA_LFLAG_NO_SRST) &&
- !sata_set_spd_needed(link) &&
- !(ehc->i.action & ATA_EH_HARDRESET))))
- tmp_action = ATA_EH_SOFTRESET;
- else
- tmp_action = ATA_EH_HARDRESET;
-
- ehc->i.action = (ehc->i.action & ~ATA_EH_RESET_MASK) | tmp_action;
+ /* prefer hardreset */
+ ehc->i.action &= ~ATA_EH_RESET;
+ if (hardreset) {
+ reset = hardreset;
+ ehc->i.action = ATA_EH_HARDRESET;
+ } else {
+ reset = softreset;
+ ehc->i.action = ATA_EH_SOFTRESET;
+ }
if (prereset) {
rc = prereset(link, jiffies + ATA_EH_PRERESET_TIMEOUT);
@@ -2177,7 +2165,7 @@
if (rc == -ENOENT) {
ata_link_printk(link, KERN_DEBUG,
"port disabled. ignoring.\n");
- ehc->i.action &= ~ATA_EH_RESET_MASK;
+ ehc->i.action &= ~ATA_EH_RESET;
ata_link_for_each_dev(dev, link)
classes[dev->devno] = ATA_DEV_NONE;
@@ -2190,12 +2178,8 @@
}
}
- /* prereset() might have modified ehc->i.action */
- if (ehc->i.action & ATA_EH_HARDRESET)
- reset = hardreset;
- else if (ehc->i.action & ATA_EH_SOFTRESET)
- reset = softreset;
- else {
+ /* prereset() might have cleared ATA_EH_RESET */
+ if (!(ehc->i.action & ATA_EH_RESET)) {
/* prereset told us not to reset, bang classes and return */
ata_link_for_each_dev(dev, link)
classes[dev->devno] = ATA_DEV_NONE;
@@ -2203,14 +2187,6 @@
goto out;
}
- /* did prereset() screw up? if so, fix up to avoid oopsing */
- if (!reset) {
- if (softreset)
- reset = softreset;
- else
- reset = hardreset;
- }
-
retry:
deadline = jiffies + ata_eh_reset_timeouts[try++];
@@ -2240,7 +2216,7 @@
goto fail;
}
- ata_eh_about_to_do(link, NULL, ATA_EH_RESET_MASK);
+ ata_eh_about_to_do(link, NULL, ATA_EH_RESET);
rc = ata_do_reset(link, reset, classes, deadline);
}
@@ -2290,7 +2266,7 @@
postreset(link, classes);
/* reset successful, schedule revalidation */
- ata_eh_done(link, NULL, ehc->i.action & ATA_EH_RESET_MASK);
+ ata_eh_done(link, NULL, ATA_EH_RESET);
ehc->i.action |= ATA_EH_REVALIDATE;
rc = 0;
@@ -2548,7 +2524,7 @@
ata_eh_detach_dev(dev);
ata_dev_init(dev);
ehc->did_probe_mask |= (1 << dev->devno);
- ehc->i.action |= ATA_EH_SOFTRESET;
+ ehc->i.action |= ATA_EH_RESET;
ehc->saved_xfer_mode[dev->devno] = 0;
ehc->saved_ncq_enabled &= ~(1 << dev->devno);
@@ -2592,12 +2568,7 @@
return 1;
} else {
- /* soft didn't work? be haaaaard */
- if (ehc->i.flags & ATA_EHI_DID_RESET)
- ehc->i.action |= ATA_EH_HARDRESET;
- else
- ehc->i.action |= ATA_EH_SOFTRESET;
-
+ ehc->i.action |= ATA_EH_RESET;
return 0;
}
}
@@ -2690,7 +2661,7 @@
ehc->i.action = 0;
/* do we need to reset? */
- if (ehc->i.action & ATA_EH_RESET_MASK)
+ if (ehc->i.action & ATA_EH_RESET)
reset = 1;
ata_link_for_each_dev(dev, link)
@@ -2708,7 +2679,7 @@
ata_port_for_each_link(link, ap) {
struct ata_eh_context *ehc = &link->eh_context;
- if (!(ehc->i.action & ATA_EH_RESET_MASK))
+ if (!(ehc->i.action & ATA_EH_RESET))
continue;
rc = ata_eh_reset(link, ata_link_nr_vacant(link),