Problems using sub-pages when NAND_VERIFY_WRITE is used

[David Lambert]

Due to some hardware problems, I tried to enable the NAND_VERIFY_WRITE 
in the 2.3.30.1 kernel on an Atmel AT91RM9200 chip. All seemed to work 
as expected until I attempted to make a UBI volume. On further 
investigation it appears to be when UBI attempts sub-page writes. I have 
narrowed the problem down by using mtd_subpagetest which also errors. 
Running mtd_pagetest runs fine, as does mtd_subpagetest on a kernel 
without NAND_VERIFY_WRITE enabled. I took a quick look in nand_base.c 
and there does not seem to be a separate verification for partial pages. 
I am quite a newbie to the kernel MTD at this level.


Thanks for any advice on where to look next,

Dave.


# echo 8 > /proc/sys/kernel/printk
# insmod 
/lib/modules/2.6.30.1/kernel/drivers/mtd/tests/mtd_subpagetest.ko dev=4

=================================================
mtd_subpagetest: MTD device: 4
mtd_subpagetest: MTD device size 104857600, eraseblock size 262144, page 
size 4096, subpage size 1024, count of eraseblocks 0, pages per 
eraseblock 0, OOB size 128
mtd_subpagetest: scanning for bad eraseblocks
mtd_subpagetest: scanned 400 eraseblocks, 0 are bad
mtd_subpagetest: erasing whole device
mtd_subpagetest: erased 400 eraseblocks
mtd_subpagetest: writing whole device
mtd_subpagetest: error: write failed at 0x400
mtd_subpagetest:   write size: 0x400
mtd_subpagetest:   written: 0x0
mtd_subpagetest: error -5 occurred
=================================================
insmod: cannot insert 
`/lib/modules/2.6.30.1/kernel/drivers/mtd/tests/mtd_subpagetest.ko': 
Input/output error (-1): Input/output error
# insmod /lib/modules/2.6.30.1/kernel/drivers/mtd/tests/mtd_pagetest.ko 
dev=4

=================================================
mtd_pagetest: MTD device: 4
mtd_pagetest: MTD device size 104857600, eraseblock size 262144, page 
size 4096, count of eraseblocks 400, pages per eraseblock 64, OOB size 128
mtd_pagetest: scanning for bad eraseblocks
mtd_pagetest: scanned 400 eraseblocks, 0 are bad
mtd_pagetest: erasing whole device
mtd_pagetest: erased 400 eraseblocks
mtd_pagetest: writing whole device
mtd_pagetest: written up to eraseblock 0
mtd_pagetest: written up to eraseblock 256
mtd_pagetest: written 400 eraseblocks
mtd_pagetest: verifying all eraseblocks
mtd_pagetest: verified up to eraseblock 0
mtd_pagetest: verified up to eraseblock 256
mtd_pagetest: verified 400 eraseblocks
mtd_pagetest: crosstest
mtd_pagetest: reading page at 0x0
mtd_pagetest: reading page at 0x63ff000
mtd_pagetest: reading page at 0x0
mtd_pagetest: verifying pages read at 0x0 match
mtd_pagetest: crosstest ok
mtd_pagetest: erasecrosstest
mtd_pagetest: erasing block 0
mtd_pagetest: writing 1st page of block 0
mtd_pagetest: reading 1st page of block 0
mtd_pagetest: verifying 1st page of block 0
mtd_pagetest: erasing block 0
mtd_pagetest: writing 1st page of block 0
mtd_pagetest: erasing block 399
mtd_pagetest: reading 1st page of block 0
mtd_pagetest: verifying 1st page of block 0
mtd_pagetest: erasecrosstest ok
mtd_pagetest: erasetest
mtd_pagetest: erasing block 0
mtd_pagetest: writing 1st page of block 0
mtd_pagetest: erasing block 0
mtd_pagetest: reading 1st page of block 0
mtd_pagetest: verifying 1st page of block 0 is all 0xff
mtd_pagetest: erasetest ok
mtd_pagetest: finished with 0 errors