Commit Graph

78 Commits

Author SHA1 Message Date
Jeff Garzik
a84471fe26 [libata] Trim trailing whitespace.
No code changes.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-26 05:51:33 -05:00
Alan
10305f0f8e Add id_to_dma_mode function for printing DMA modes
Also export dev_disable as this is needed by drivers doing slave decode
filtering, which will follow shortly

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-25 15:41:40 -05:00
Tejun Heo
44877b4e22 libata: s/ap->id/ap->print_id/g
ata_port has two different id fields - id and port_no.  id is
system-wide 1-based unique id for the port while port_no is 0-based
host-wide port number.  The former is primarily used to identify the
ATA port to the user in printk messages while the latter is used in
various places in libata core and LLDs to index the port inside the
host.

The two fields feel quite similar and sometimes ap->id is used in
place of ap->port_no, which is very difficult to spot.  This patch
renames ap->id to ap->print_id to reduce the possibility of such bugs.

Some printk messages are adjusted such that id string (ata%u[.%u])
isn't printed twice and/or to use ata_*_printk() instead of hardcoded
id format.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:20 -05:00
Magnus Damm
9dd6fa3231 libata: Remove duplicate dma blacklist entry
libata: Remove duplicate dma blacklist entry

The exact same entry is already present.

Signed-off-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:19 -05:00
Tejun Heo
6d1245bf29 libata: separate out ata_ncq_enabled()
Separate out ata_ncq_enabled().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:18 -05:00
Tejun Heo
4c90d9717a libata: disable pdev on all suspend events
libata used disable pdev only on PM_EVENT_SUSPEND while re-enable pdev
unconditionally.  This was okay before ref-counted pdev enable update
but it now makes the pdev pinned after swsusp cycle (enabled twice but
disabled only once) and devres sanity check whines about it.

Fix it by unconditionally disabling pdev on all suspend events.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:18 -05:00
Tejun Heo
4d05447ec7 libata: fix probe_ent alloc/free bugs
ata_probe_ent_alloc() had a temporary hack such that devm_kzalloc()
was used for allocation if devres had been previously initialized on
the device; otherwise, plain kzalloc() was used.  This was to make the
code useable from both the old and devres-aware libata drivers during
transition.  This hack made ata_sas_port_alloc() unable to determine
how the probe_ent is allocated, causing double free in some cases.

Remove the now-unneeded hack and make ata_sas_port_alloc() use
devm_kfree().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: James Bottomley <James.Bottomley@SteelEye.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:17 -05:00
Tejun Heo
909706a247 libata: kill ATA_DNXFER_ANY
ATA_DNXFER_ANY isn't used anymore.  Kill it.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:17 -05:00
Tejun Heo
4ae72a1e46 libata: improve probe failure handling
* Move forcing device to PIO0 on device disable into
  ata_dev_disable().  This makes both old and new EHs act the same
  way.

* Speed down only PIO mode on probe failure.  All commands used during
  probing are PIO commands.  There's no point in speeding down DMA.

* Retry at least once after -ENODEV.  Some devices report garbled
  IDENTIFY data after certain events.  This shouldn't cause device
  detach and re-attach.

* Rearrange EH failure path for simplicity.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:16 -05:00
Tejun Heo
458337dbb1 libata: improve ata_down_xfermask_limit()
Make ata_down_xfermask_limit() accept @sel instead of @force_pio0.
@sel selects how the xfermask limit will be adjusted.  The following
selectors are defined.

* ATA_DNXFER_PIO	: only speed down PIO
* ATA_DNXFER_DMA	: only speed down DMA, don't cause transfer mode change
* ATA_DNXFER_40C	: apply 40c cable limit
* ATA_DNXFER_FORCE_PIO	: force PIO
* ATA_DNXFER_FORCE_PIO0	: force PIO0 (same as original with @force_pio0 == 1)
* ATA_DNXFER_ANY	: same as original with @force_pio0 == 0

Currently, only ANY and FORCE_PIO0 are used to maintain the original
behavior.  Other selectors will be used later to improve EH speed down
sequence.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:16 -05:00
Akira Iguchi
a619f981b4 libata: PATA driver for Celleb
This is the patch for PATA controller of Celleb.

This driver uses the managed iomap (devres).

Because this driver needs special taskfile accesses, there is
a copy of ata_std_softreset(). ata_dev_try_classify() is exported
so that it can be used in this function.

Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-21 04:58:16 -05:00
Kristen Carlson Accardi
08573a86c8 [PATCH] libata: change order of _SDD/_GTF execution (resend #3)
Make the sdd call come before gtf.  _SDD is used to provide
input to the _GTF file, so it should be executed first.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
(cherry picked from 89d74215e1e5b79ea084385b5c83d0e33cf2d655 commit)
2007-02-16 13:32:41 -05:00
Kristen Carlson Accardi
7ea1fbc2a2 [PATCH] libata: ACPI _SDD support
_SDD (Set Device Data) is an ACPI method that is used to tell the
firmware what the identify data is of the device that is attached to
the port.  It is an optional method, and it's ok for it to be missing.
Because of this, we always return success from the routine that calls
this method, even if the execution fails.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
(cherry picked from 39aa79e0a1f5f2e28aa341f035940746a98b45b1 commit)
2007-02-16 13:32:41 -05:00
Kristen Carlson Accardi
11ef697b37 [PATCH] libata: ACPI and _GTF support
_GTF is an acpi method that is used to reinitialize the drive.  It returns
a task file containing ata commands that are sent back to the drive to restore
it to boot up defaults.

Signed-off-by: Kristen Carlson Accardi <kristen.c.accardi@intel.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
(cherry picked from 9c69cab24b51a89664f4c0dfaf8a436d32117624 commit)
2007-02-16 13:32:41 -05:00
Tejun Heo
81afe89318 libata: clear TF before IDENTIFYing
Some devices chock if Feature is not clear when IDENTIFY is issued.
Set ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE for IDENTIFY such that whole
TF is cleared when reading ID data.

Kudos to Art Haas for testing various futile patches over several
months and Mark Lord for pointing out the fix.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Art Haas <ahaas@airmail.net>
Cc: Mark Lord <mlord@pobox.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-15 18:04:01 -05:00
Jeff Garzik
591a6e8ee7 libata: build fix after dmesg probe output changes
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:40 -05:00
Alan
11750a40ab libata: Early CFA adapters are not required to support mode setting
If we are doing a PIO setup for a CFA card and it blows up with a device
error then assume it is an older CFA card which doesn't support this
rather than failing the device out of existance.

Stands seperate to the quieting patch but that is obviously useful with
this change.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:40 -05:00
Tejun Heo
34fee227dd libata: add 150ms between completion of hardreset and status checking
Follow the old SRST rule and delay 150ms between completion of
hardreset and status checking.  Debouncing delay should usually cover
this but debounce duration could be shorter than 150ms under certain
circumstances.

Usefulness depends on host controller implementation but it can't hurt
and serves as a reminder that 2s delay for GoVault should also be
added here.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:38 -05:00
Eric D. Mudama
3f64f565be libata: rearrange dmesg info to add full ATA revision
Per Jeff's suggestion, this patch rearranges the info printed for ATA
drives into dmesg to add the full ATA firmware revision and model
information, while keeping the output to 2 lines.

Signed-off-by: Eric D. Mudama <edmudama@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:38 -05:00
Akira Iguchi
836250069f libata: add another IRQ calls (core and headers)
This patch is against the libata core and headers.

Two IRQ calls are added in ata_port_operations.
- irq_on() is used to enable interrupts.
- irq_ack() is used to acknowledge a device interrupt.

In most drivers, ata_irq_on() and ata_irq_ack() are used for
irq_on and irq_ack respectively.

In some drivers (ex: ahci, sata_sil24) which cannot use them
as is, ata_dummy_irq_on() and ata_dummy_irq_ack() are used.

Signed-off-by: Kou Ishizaki <kou.ishizaki@toshiba.co.jp>
Signed-off-by: Akira Iguchi <akira2.iguchi@toshiba.co.jp>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:38 -05:00
Tejun Heo
0d5ff56677 libata: convert to iomap
Convert libata core layer and LLDs to use iomap.

* managed iomap is used.  Pointer to pcim_iomap_table() is cached at
  host->iomap and used through out LLDs.  This basically replaces
  host->mmio_base.

* if possible, pcim_iomap_regions() is used

Most iomap operation conversions are taken from Jeff Garzik
<jgarzik@pobox.com>'s iomap branch.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:38 -05:00
Jeff Garzik
fda0efc597 [libata] Shuffle DRV_xxx in core and SiS drivers, to kill warnings
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:37 -05:00
Tejun Heo
b878ca5d37 libata: remove unused functions
Now that all LLDs are converted to use devres, default stop callbacks
are unused.  Remove them.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:37 -05:00
Tejun Heo
f0d36efdc6 libata: update libata core layer to use devres
Update libata core layer to use devres.

* ata_device_add() acquires all resources in managed mode.

* ata_host is allocated as devres associated with ata_host_release.

* Port attached status is handled as devres associated with
  ata_host_attach_release().

* Initialization failure and host removal is handedl by releasing
  devres group.

* Except for ata_scsi_release() removal, LLD interface remains the
  same.  Some functions use hacky is_managed test to support both
  managed and unmanaged devices.  These will go away once all LLDs are
  updated to use devres.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:37 -05:00
Tejun Heo
0529c159db libata: implement ata_host_detach()
Implement ata_host_detach() which calls ata_port_detach() for each
port in the host and export it.  ata_port_detach() is now internal and
thus un-exported.  ata_host_detach() will be used as the 'deregister
from libata layer' function after devres conversion.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:37 -05:00
Alan
18d90deb07 libata: trivial stuff
Readability/typos etc

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:34 -05:00
Tejun Heo
726f0785b6 libata: kill qc->nsect and cursect
libata used two separate sets of variables to record request size and
current offset for ATA and ATAPI.  This is confusing and fragile.
This patch replaces qc->nsect/cursect with qc->nbytes/curbytes and
kills them.  Also, ata_pio_sector() is updated to use bytes for
qc->cursg_ofs instead of sectors.  The field used to be used in bytes
for ATAPI and in sectors for ATA.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:31 -05:00
Tejun Heo
553c4aa630 libata: handle pci_enable_device() failure while resuming
Handle pci_enable_device() failure while resuming.  This patch kills
the "ignoring return value of 'pci_enable_device'" warning message and
propagates __must_check through ata_pci_device_do_resume().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:30 -05:00
Tejun Heo
8bfa79fcb8 libata: use ata_id_c_string()
There were several places where ATA ID strings are manually terminated
and in some places possibly unterminated strings were passed to string
functions which don't limit length like strstr().  This patch converts
all of them over to ata_id_c_string().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:30 -05:00
Tejun Heo
a0cf733b33 libata: straighten out ATA_ID_* constants
* Kill _OFS suffixes in ATA_ID_{SERNO|FW_REV|PROD}_OFS for consistency
  with other ATA_ID_* constants.

* Kill ATA_SERNO_LEN

* Add and use ATA_ID_SERNO_LEN, ATA_ID_FW_REV_LEN and ATA_ID_PROD_LEN.
  This change also makes ata_device_blacklisted() use proper length
  for fwrev.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:30 -05:00
Adrian Bunk
7102d230d6 drivers/ata/: make 4 functions static
This patch makes the following needlessly global functions static:
- libata-core.c: ata_qc_complete_internal()
- libata-scsi.c: ata_scsi_qc_new()
- libata-scsi.c: ata_dump_status()
- libata-scsi.c: ata_to_sense_error()

Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:30 -05:00
Jeff Garzik
f20b16ff7c [libata] trim trailing whitespace
Most of these contributed by that mysterious figger known as A.C.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-09 17:39:29 -05:00
Brian King
49c8042996 libata: Initialize nbytes for internal sg commands
Some LLDDs, like ipr, use nbytes and pad_len to determine
the total data transfer length of a command. Make sure
nbytes gets initialized for internally generated commands.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-02-02 11:52:05 -05:00
Lennert Buytenhek
7a0f1c8a4b ata_if_xfermask() word 51 fix
If word 53 bit 1 isn't set, the maximum PIO mode is indicated by
the upper 8 bits of word 51, not the lower 8 bits.  Fixes PIO mode
detection on old Compact Flash cards.

Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-01-30 09:14:56 -05:00
Alan
b229a7b0ae libata: set_mode, Fix the FIXME
When set_mode() changed ->set_mode didn't adapt. This makes the needed
changes and removes the relevant FIXME case.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2007-01-24 19:55:16 -05:00
Tejun Heo
33480a0ede [PATCH] libata: don't initialize sg in ata_exec_internal() if DMA_NONE (take #2)
Calling sg_init_one() with NULL buf causes oops on certain
configurations.  Don't initialize sg in ata_exec_internal() if
DMA_NONE and make the function complain if @buf is NULL when dma_dir
isn't DMA_NONE.  While at it, fix comment.

The problem is discovered and initial patch was submitted by Arnd
Bergmann.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Cc: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-12-16 10:13:22 -05:00
Alan
fd3367af3d [PATCH] libata: Incorrect timing computation for PIO5/6
The ata timing computation code makes some mistakes in PIO5/6 because a
check was not updated correctly when I put this support into the kernel.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-12-07 07:37:07 -05:00
Albert Lee
e3472cbe5c [PATCH] libata: let ATA_FLAG_PIO_POLLING use polling pio for ATA_PROT_NODATA
Even if ATA_FLAG_PIO_POLLING is set, libata uses irq pio for the ATA_PROT_NODATA protocol.
This patch let ATA_FLAG_PIO_POLLING use polling pio for the ATA_PROT_NODATA protocol.

Signed-off-by: Albert Lee <albertcc@tw.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-12-07 07:22:28 -05:00
David Howells
9db7372445 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6
Conflicts:

	drivers/ata/libata-scsi.c
	include/linux/libata.h

Futher merge of Linus's head and compilation fixups.

Signed-Off-By: David Howells <dhowells@redhat.com>
2006-12-05 17:01:28 +00:00
Tejun Heo
800b399669 [PATCH] libata: always use polling IDENTIFY
libata switched to IRQ-driven IDENTIFY when IRQ-driven PIO was
introduced.  This has caused a lot of problems including device
misdetection and phantom device.

ATA_FLAG_DETECT_POLLING was added recently to selectively use polling
IDENTIFY on problemetic drivers but many controllers and devices are
affected by this problem and trying to adding ATA_FLAG_DETECT_POLLING
for each such case is diffcult and not very rewarding.

This patch makes libata always use polling IDENTIFY.  This is
consistent with libata's original behavior and drivers/ide's behavior.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-12-03 07:58:10 -05:00
Tejun Heo
70e6ad0c6d [PATCH] libata: prepare ata_sg_clean() for invocation from EH
Make ata_sg_clean() global and don't allow NCQ for internal commands.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-12-03 17:56:24 +09:00
Tejun Heo
bd056d7eeb [PATCH] libata: separate out rw ATA taskfile building into ata_build_rw_tf()
Separate out rw ATA taskfile building from ata_scsi_rw_xlat() into
ata_build_rw_tf().  This will be used to improve media error handling.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-12-03 17:56:24 +09:00
Tejun Heo
2432697ba0 [PATCH] libata: implement ata_exec_internal_sg()
Sg'ify ata_exec_internal() and call it ata_exec_internal_sg().
Wrapper function around ata_exec_internal_sg() is implemented to
provide ata_exec_internal() interface.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-12-03 17:56:24 +09:00
Tejun Heo
0f0a3ad374 [PATCH] libata: make sure IRQ is cleared after ata_bmdma_freeze()
Now that BMDMA status is recorded in irq handler.  ata_bmdma_freeze()
is free to manipulate host status.  Under certain circumstances, some
controllers (ICH7 in enhanced mode w/ IRQ shared) raise IRQ when CTL
register is written to and ATA_NIEN doesn't mask it.

This patch makes ata_bmdma_freeze() clear all pending IRQs after
freezing a port.  This change makes explicit clearing in
ata_device_add() unnecessary and thus kills it.  The removed code was
SFF-specific and was in the wrong place.

Note that ->freeze() handler is always called under ap->lock held and
irq disabled.  Even if CTL manipulation causes stuck IRQ, it's cleared
immediately.  This should be safe (enough) even in SMP environment.
More correct solution is to mask the IRQ from IRQ controller but that
would be an overkill.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-12-03 17:56:24 +09:00
Tejun Heo
ea54763f8a [PATCH] libata: move BMDMA host status recording from EH to interrupt handler
For certain errors, interrupt handler alter BMDMA host status before
entering EH (clears active and intr).  Thus altered BMDMA host status
value is recorded by BMDMA EH and reported to user.  Move BMDMA host
status recording from EH to interrupt handler.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-12-03 17:56:24 +09:00
Tejun Heo
3d3cca3755 [PATCH] libata: implement ATA_FLAG_SETXFER_POLLING and use it in pata_via, take #2
This patch implements ATA_FLAG_SETXFER_POLLING and use in pata_via.
If this flag is set, transfer mode setting performed by polling not by
interrupt.  This should help those controllers which raise interrupt
before the command is actually complete on SETXFER.

Rationale for this approach.

* uses existing facility and relatively simple
* no busy sleep in the interrupt handler
* updating drivers is easy

While at it, kill now unused flag ATA_FLAG_SRST in pata_via.

Signed-off-by: Tejun Heo <htejun@gmail.com>
2006-12-03 17:56:23 +09:00
Tejun Heo
35b649fe25 [PATCH] libata: implement ata_tf_read_block()
Implement ata_tf_read_block().

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-12-01 22:46:00 -05:00
Tejun Heo
39599a5334 [PATCH] libata: sync result_tf.flags w/ command tf.flags
libata didn't initialize result_tf.flags which indicates transfer type
(RW/FUA) and address type (CHS/LBA/LBA48).  ata_gen_fixed_sense()
assumed result_tf.flags equals command tf.flags and failed to report
the first failed block to SCSI layer because zero tf flags indicates
CHS and bad block reporting for CHS is not implemented.

Implement fill_result_tf() which sets result_tf.flags to command
tf.flags and use it to fill result_tf.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-12-01 22:45:59 -05:00
Tejun Heo
61c0596c5f [PATCH] libata: trivial updates to ata_sg_init_one()
There's no need to memset &qc->sgent manually, sg_init_one() clears
sgent inside it.  Also, kill not-so-necessary sg local variable.

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-12-01 22:45:57 -05:00
Tejun Heo
55a8e2c83c [PATCH] libata: implement presence detection via polling IDENTIFY
On some controllers (ICHs in piix mode), there is *NO* reliable way to
determine device presence other than issuing IDENTIFY and see how the
transaction proceeds by watching the TF status register.

libata acted this way before irq-pio and phantom devices caused very
little problem but now that IDENTIFY is performed using IRQ drive PIO,
such phantom devices now result in multiple 30sec timeouts during
boot.

This patch implements ATA_FLAG_DETECT_POLLING.  If a LLD sets this
flag, libata core issues the initial IDENTIFY in polling mode and if
the initial data transfer fails w/ HSM violation, the port is
considered to be empty thus replicating the old libata and IDE
behavior.

Signed-off-by: Jeff Garzik <jeff@garzik.org>
2006-12-01 22:45:55 -05:00