1 What: /sys/class/ata_...
3 Contact: Gwendal Grignou<gwendal@google.com>
6 Provide a place in sysfs for storing the ATA topology of the system. This allows
7 retrieving various information about ATA objects.
9 Files under /sys/class/ata_port
10 -------------------------------
12 For each port, a directory ataX is created where X is the ata_port_id of
13 the port. The device parent is the ata host device.
17 Number of IRQ received by the port while idle [some ata HBA only].
21 If a SATA Port Multiplier (PM) is connected, number of link behind it.
23 Files under /sys/class/ata_link
24 -------------------------------
26 Behind each port, there is a ata_link. If there is a SATA PM in the
27 topology, 15 ata_link objects are created.
29 If a link is behind a port, the directory name is linkX, where X is
30 ata_port_id of the port.
31 If a link is behind a PM, its name is linkX.Y where X is ata_port_id
32 of the parent port and Y the PM port.
36 Maximum speed supported by the connected SATA device.
40 Maximum speed imposed by libata.
44 Current speed of the link [1.5, 3Gps,...].
46 Files under /sys/class/ata_device
47 ---------------------------------
49 Behind each link, up to two ata device are created.
50 The name of the directory is devX[.Y].Z where:
51 - X is ata_port_id of the port where the device is connected,
52 - Y the port of the PM if any, and
53 - Z the device id: for PATA, there is usually 2 devices [0,1],
57 Device class. Can be "ata" for disk, "atapi" for packet device,
58 "pmp" for PM, or "none" if no device was found behind the link.
62 DMA transfer mode used by the device.
63 Mostly used by PATA device.
67 PIO transfer mode used by the device.
68 Mostly used by PATA device.
72 Current transfer mode.
73 Mostly used by PATA device.
77 Cached result of IDENTIFY command, as described in ATA8 7.16 and 7.17.
78 Only valid if the device is not a PM.
82 Cached result of the dump of PM GSCR register.
84 0: SATA_PMP_GSCR_PROD_ID,
86 2: SATA_PMP_GSCR_PORT_INFO,
87 32: SATA_PMP_GSCR_ERROR,
88 33: SATA_PMP_GSCR_ERROR_EN,
89 64: SATA_PMP_GSCR_FEAT,
90 96: SATA_PMP_GSCR_FEAT_EN,
91 130: SATA_PMP_GSCR_SII_GPIO
92 Only valid if the device is a PM.
96 Shows the DSM TRIM mode currently used by the device. Valid
98 unsupported: Drive does not support DSM TRIM
99 unqueued: Drive supports unqueued DSM TRIM only
100 queued: Drive supports queued DSM TRIM
101 forced_unqueued: Drive's queued DSM support is known to be
102 buggy and only unqueued TRIM commands
107 Number of time libata decided to lower the speed of link due to errors.
111 Formatted output of the error ring of the device.