Re: [PATCH] libata error handling fixes (ATAPI)

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Tejun Heo wrote:
* prb->fis doesn't contain proper signature after phy reset. I just

This makes sense. Each PRB slot in the card's RAM only contains something useful after you have submitted a PRB, and had some results returned.


* As all commands hang after failed TUR, which BTW fails rightfully with 06h (UNIT ATTENTION due to prior reset) and then 02h's (NOT READY), I avoided TUR failures by issuing REQUEST SENSE first, which returns NO SENSE but does clear UA condition, and then waiting for more than 10secs to give the drive time to become ready.

10 seconds is certainly a long time.

grep for msleep(150) in libata code, though.


* With above two changes, no command fails and I can mount the cdrom.

------------------

And here are things that I've found out so far....

* ATAPI commands without data (TEST_UNIT_READY, ALLOW_MEDIUM_REMOVAL...) work happily with any prb->ctrl flag (no flag, PRB_CTRL_PACKET_READ or PRB_CTRL_PACKET_WRITE).

I suppose no-flag is the right answer, then...


* Currently, sil24_reset_controller() is called on every error interrupt to make sure the controller is ready for further operation. Unfortunately, the current reset_controller() seems to reset PHY too. The drive becomes NOT READY after reset_controller(). So, when TUR fails, it falls into TUR, fail with NOT READY, reset which makes the drive NOT READY again cycle.

Standard init sequence includes checking SStatus, then if a device is present, waiting until Port Ready (bit 31) of PORT_CTRL_STAT is set. It doesn't look like sata_sil24 does that.


* Wihtout sil24_reset_controller(), no further command can be issued. The controller doesn't seem to be operating normally after DEV_ERR.

The port stops, when any error occurs. For device errors, set PORT_CS_INIT bit in PORT_CTRL_STAT, then wait for Port Ready (bit 31, see above).


So, what we need to know to make sil24 work happily with ATAPI devices.

* How to get device signature on initialization.

AFAICS, you _must_ send a soft reset PRB. This will be needed anyway, for port multiplier support.


* How to make the controller operational again after a DEV_ERR without affecting the attached device.

Assert PORT_CS_INIT, then wait for Port Ready. __ONLY__ do this for errors PORT_CERR_DEV and PORT_CERR_SDB.

	Jeff


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux