I am submitting this fast-track on behalf of myself, with
timeout set to 08/28/2007. Patch/update binding requesed.
-jg
------------
Identification of Drivers Registering Devids
Summary
This case proposes a new property, 'ddi-devid-registrant'. This
property will be specified in the driver.conf(4) files of target
drivers that call ddi_devid_register(9F) [8]. Instead of using
compiled-in tables, the IO framework will use this new information
to identify drivers of interest when there is a devid cache [3]
miss. NOTE: This property is similar in purpose to the
'ddi-vhci-class' property approved by [1].
Immediate consumers (sd, ssd, cmdk, and dad target drivers) are all
in ON. There are no contracts needed at this time. I am seeking
patch binding.
Proposal
The IO framework maintains a private cache that maps devids to
/devices paths [3]. If the cache is corrupted, deleted, or the
requested mapping is not in the cache the IO framework must still
perform a best-effort search to resolve a devid to a /devices path.
For this best-effort search the IO framework attaches all instances
of all drivers that register devids. To do this, the IO framework
currently has a compiled-in table containing the names of drivers
known to register a devid.
The compiled-in list of driver names is a maintenance overhead since
the list needs to be updated whenever a new driver that a registers
devid is added to the system (or an existing one is removed). To
eliminate this overhead, the proposal is to remove this compiled-in
list and replace it with a mechanism based on the
'ddi-devid-registrant' property.
The proposed 'ddi-devid-registrant' property will be specified in
the driver.conf file of each target driver that calls
ddi_devid_register(9F). The IO framework will be modified to use
this information instead of compiled-in tables.
Interface Summary
Interface Level Comments
-------------------------------------------------------------------------
ddi-devid-registrant Committed Property to indicate a driver may
register a devid for a device
Man page update
Kernel Functions for Drivers ddi_devid_compare(9F)
NAME
ddi_devid_register, <...>
SYNOPSIS
<...>
int ddi_devid_register(dev_info_t *dip, ddi_devid_t devid );
<...>
DESCRIPTION
<...>
ddi_devid_register() registers the device ID address (devid)
with the DDI framework, associating it with the dev_info
passed in (dip). The drivers must register device IDs at
attach time. See attach(9E).
+
+ A driver which calls ddi_devid_register() should place the
+ following line in its driver.conf(4) file. The presence of
+ this property informs the system that this driver may
+ register a devid for a device when device discovery is
+ necessary.
+
+ ddi-devid-registrant=1;
+
References
[1] PSARC/2006/285 MPxIO Driver Properties
http://sac.sfbay/arc/PSARC/2006/285/
[2] PSARC/2004/504 Common Devid/GUID Encode Interfaces for SCSI Devices
http://sac.sfbay/PSARC/2004/504/
[3] PSARC/2004/064 Devid Cache
http://sac.sfbay/PSARC/2004/064/
[4] PSARC/2003/123 Devids for disksets
http://sac.sfbay/PSARC/2003/123/
[5] PSARC/2001/559 New Devid Type for ATA Drives
http://sac.sfbay/PSARC/2001/559/
[6] PSARC/2000/480 Devid Enhancements
http://sac.sfbay/PSARC/2000/480/
[7] PSARC/1999/357 Devid Issues
http://sac.sfbay/PSARC/1999/357/
[8] PSARC/1995/352 Disk Id
http://sac.sfbay/PSARC/1995/352/
