another issue with ubifs on v3.6-rc2: attaching an formatted device

[Uwe Kleine-König]

Hello,

On Tue, Aug 21, 2012 at 01:15:13PM +0300, Artem Bityutskiy wrote:
> On Tue, 2012-08-21 at 11:35 +0200, Uwe Kleine-König wrote:
> > On Mon, Aug 20, 2012 at 10:11:07PM +0300, Artem Bityutskiy wrote:
> > > On Mon, 2012-08-20 at 18:07 +0200, Uwe Kleine-König wrote:
> > > > [  163.714143] uncorrectable error : 
> > > > [  163.727597] UBI warning: ubi_io_read: error -74 (ECC error) while
> > > > reading 64 bytes from PEB 0:0, read only 64 bytes, retry
> > > > [  163.740737] uncorrectable error : 
> > > > [  163.744032] UBI warning: ubi_io_read: error -74 (ECC error) while
> > > > reading 64 bytes from PEB 0:0, read only 64 bytes, retry
> > > > [  163.757119] uncorrectable error : 
> > > > [  163.760487] UBI warning: ubi_io_read: error -74 (ECC error) while
> > > > reading 64 bytes from PEB 0:0, read only 64 bytes, retry
> > > > [  163.774427] uncorrectable error : 
> > > > [  163.777808] UBI error: ubi_io_read: error -74 (ECC error) while
> > > > reading 64 bytes from PEB 0:0, read 64 bytes 
> > > 
> > > This looks like your flash does not really support sub-pages while
> > > declares that it does. Check it with MTD subpage test.
> > the subpages test fails with:
> > 
> > [   82.435792] mtd_subpagetest: written up to eraseblock 7424
> > [   82.905775] mtd_subpagetest: written up to eraseblock 7680
> > [   83.375201] mtd_subpagetest: written up to eraseblock 7936
> > [   83.840447] mtd_subpagetest: written 8192 eraseblocks
> > [   83.845522] mtd_subpagetest: verifying all eraseblocks
> > [   83.852740] uncorrectable error : 
> > [   83.856086] mtd_subpagetest: error: read failed at 0x0
> > [   83.861469] mtd_subpagetest: error -74 occurred
> > [   83.866093] =================================================
> > Error: could not insert module ./drivers/mtd/tests/mtd_subpagetest.ko: Bad message
> > 
> > I don't have a clue yet how to debug that further. Will start with
> > checking older kernel releases. Any hints welcome.
> 
> AFAIR, the driver did not support subpages and just needed to report
> about this. And there is a bug in MTD which makes it impossible for
> drivers to tell that sub-pages are not supported. So AFAIU, we need the
> patch I pointed you, and we also need the driver to use "no subpage
> writes" option.
I enabled hwecc and then both mtd_subpagetest and ubi-mounting worked
again. Maybe it would make sense to drop swecc?

Many thanks to Artem who helped debugging that on irc.

Best regards
Uwe

-- 
Pengutronix e.K.                           | Uwe Kleine-König            |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |