Commits
Thomas Petazzoni committed 54c39e9ba3a
mtd: nand: reduce the warning noise when the ECC is too weak
In commit 67a9ad9b8a6f ("mtd: nand: Warn the user if the selected ECC
strength is too weak"), a check was added to inform the user when the
ECC used for a NAND device is weaker than the recommended ECC
advertised by the NAND chip. However, the warning uses WARN_ON(),
which has two undesirable side-effects:
- It just prints to the kernel log the fact that there is a warning
in this file, at this line, but it doesn't explain anything about
the warning itself.
- It dumps a stack trace which is very noisy, for something that the
user is most likely not able to fix. If a certain ECC used by the
kernel is weaker than the advertised one, it's most likely to make
sure the kernel uses an ECC that is compatible with the one used by
the bootloader, and changing the bootloader may not necessarily be
easy. Therefore, normal users would not be able to do anything to
fix this very noisy warning, and will have to suffer from it at
every kernel boot. At least every time I see this stack trace in my
kernel boot log, I wonder what new thing is broken, just to realize
that it's once again this NAND ECC warning.
Therefore, this commit turns:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1 at /home/thomas/projets/linux-2.6/drivers/mtd/nand/nand_base.c:4051 nand_scan_tail+0x538/0x780()
Modules linked in:
CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.0-rc3-dirty #4
[<c000e3dc>] (unwind_backtrace) from [<c000bee4>] (show_stack+0x10/0x14)
[<c000bee4>] (show_stack) from [<c0018180>] (warn_slowpath_common+0x6c/0x8c)
[<c0018180>] (warn_slowpath_common) from [<c001823c>] (warn_slowpath_null+0x1c/0x24)
[<c001823c>] (warn_slowpath_null) from [<c02c50cc>] (nand_scan_tail+0x538/0x780)
[<c02c50cc>] (nand_scan_tail) from [<c0639f78>] (orion_nand_probe+0x224/0x2e4)
[<c0639f78>] (orion_nand_probe) from [<c026da00>] (platform_drv_probe+0x18/0x4c)
[<c026da00>] (platform_drv_probe) from [<c026c1f4>] (really_probe+0x80/0x218)
[<c026c1f4>] (really_probe) from [<c026c47c>] (__driver_attach+0x98/0x9c)
[<c026c47c>] (__driver_attach) from [<c026a8f0>] (bus_for_each_dev+0x64/0x94)
[<c026a8f0>] (bus_for_each_dev) from [<c026bae4>] (bus_add_driver+0x144/0x1ec)
[<c026bae4>] (bus_add_driver) from [<c026cb00>] (driver_register+0x78/0xf8)
[<c026cb00>] (driver_register) from [<c026da5c>] (platform_driver_probe+0x20/0xb8)
[<c026da5c>] (platform_driver_probe) from [<c00088b8>] (do_one_initcall+0x80/0x1d8)
[<c00088b8>] (do_one_initcall) from [<c0620c9c>] (kernel_init_freeable+0xf4/0x1b4)
[<c0620c9c>] (kernel_init_freeable) from [<c049a098>] (kernel_init+0x8/0xec)
[<c049a098>] (kernel_init) from [<c00095f0>] (ret_from_fork+0x14/0x24)
---[ end trace 62f87d875aceccb4 ]---
Into the much shorter, and much more useful:
nand: WARNING: MT29F2G08ABAEAWP: the ECC used on your system is too weak compared to the one required by the NAND chip
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>