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authorTejun Heo <htejun@gmail.com>2006-11-10 18:08:10 +0900
committerJeff Garzik <jeff@garzik.org>2006-12-01 22:45:55 -0500
commit55a8e2c83ce50548dfef74bb19dfe2b809cb3099 (patch)
tree1d5ed12c49a254364f9009e9cdbf4609b92f3afb /drivers/ata/libata.h
parentbff0464769f2a1bd348265de704471747378e247 (diff)
downloadlinux-55a8e2c83ce50548dfef74bb19dfe2b809cb3099.tar.bz2
[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>
Diffstat (limited to 'drivers/ata/libata.h')
-rw-r--r--drivers/ata/libata.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/ata/libata.h b/drivers/ata/libata.h
index bb98390aa01a..be2ac39f013b 100644
--- a/drivers/ata/libata.h
+++ b/drivers/ata/libata.h
@@ -42,6 +42,8 @@ struct ata_scsi_args {
enum {
/* flags for ata_dev_read_id() */
ATA_READID_POSTRESET = (1 << 0), /* reading ID after reset */
+ ATA_READID_DETECT = (1 << 1), /* perform presence detection
+ * using polling IDENTIFY */
};
extern struct workqueue_struct *ata_aux_wq;