3.11-stable review patch. If anyone has any objections, please let me know. ------------------ From: Brian Norris <computersforpeace@xxxxxxxxx> commit 68e8078072e802e77134664f11d2ffbfbd2f8fbe upstream. The code for NAND_BUSWIDTH_AUTO is broken. According to Alexander: "I have a problem with attach NAND UBI in 16 bit mode. NAND works fine if I specify NAND_BUSWIDTH_16 option, but not working with NAND_BUSWIDTH_AUTO option. In second case NAND chip is identifyed with ONFI." See his report for the rest of the details: http://lists.infradead.org/pipermail/linux-mtd/2013-July/047515.html Anyway, the problem is that nand_set_defaults() is called twice, we intend it to reset the chip functions to their x16 buswidth verions if the buswidth changed from x8 to x16; however, nand_set_defaults() does exactly nothing if called a second time. Fix this by hacking nand_set_defaults() to reset the buswidth-dependent functions if they were set to the x8 version the first time. Note that this does not do anything to reset from x16 to x8, but that's not the supported use case for NAND_BUSWIDTH_AUTO anyway. Signed-off-by: Brian Norris <computersforpeace@xxxxxxxxx> Reported-by: Alexander Shiyan <shc_work@xxxxxxx> Tested-by: Alexander Shiyan <shc_work@xxxxxxx> Cc: Matthieu Castet <matthieu.castet@xxxxxxxxxx> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@xxxxxxxxxxxxxxx> Signed-off-by: David Woodhouse <David.Woodhouse@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/mtd/nand/nand_base.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/drivers/mtd/nand/nand_base.c +++ b/drivers/mtd/nand/nand_base.c @@ -2793,7 +2793,9 @@ static void nand_set_defaults(struct nan if (!chip->select_chip) chip->select_chip = nand_select_chip; - if (!chip->read_byte) + + /* If called twice, pointers that depend on busw may need to be reset */ + if (!chip->read_byte || chip->read_byte == nand_read_byte) chip->read_byte = busw ? nand_read_byte16 : nand_read_byte; if (!chip->read_word) chip->read_word = nand_read_word; @@ -2801,9 +2803,9 @@ static void nand_set_defaults(struct nan chip->block_bad = nand_block_bad; if (!chip->block_markbad) chip->block_markbad = nand_default_block_markbad; - if (!chip->write_buf) + if (!chip->write_buf || chip->write_buf == nand_write_buf) chip->write_buf = busw ? nand_write_buf16 : nand_write_buf; - if (!chip->read_buf) + if (!chip->read_buf || chip->read_buf == nand_read_buf) chip->read_buf = busw ? nand_read_buf16 : nand_read_buf; if (!chip->scan_bbt) chip->scan_bbt = nand_default_bbt; -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html