Hello Boris,
Am 21.04.2016 um 10:58 schrieb Boris Brezillon:
On Tue, 2 Feb 2016 11:54:35 +0100 Heiko Schocher hs@denx.de wrote:
Set free_count to zero before walking through ai->erase list in wl_init().
As U-Boot has no workqueue/threads, it immediately calls erase_worker(), which increase for each erased block free_count. Without this patch, free_count gets after this initialized to zero in wl_init(), so the free_count variable always has the maybe wrong value 0.
Detected this behaviour on the dxr2 board, where the UBI fastmap gets not written when attaching/dettaching on an empty NAND. It drops instead the error message:
could not find any anchor PEB
With this patch, fastmap gets written on dettach.
I ran into the same problem, and produced the exact same patch to fix it, so
Reviewed-by: Boris Brezillon boris.brezillon@free-electrons.com
Thanks!
I did not yet found time, to investigate this problem deeper, sorry.
The real reason to me seems, on an empty nand flash, we call scan_all() which calls scan_peb() which calls ubi_io_read_ec_hdr() which returns UBI_IO_FF as the nand is empty.
This adds the PEB to the erase list, and here comes the difference between U-Boot and linux, we have no threads in U-Boot, so we call the erase_worker function immediately ... which increments the "ubi->free_count" variable ... after that it get set to "ubi->free_count = 0" ... which leads into the error we see ...
No idea, if the correct fix not would be to move this erase_worker call after the attach phase ended, as Richard suggested, or if this fix is also valid ...
Do you have some time to check such a fix as Richard suggested?
bye, Heiko
Signed-off-by: Heiko Schocher hs@denx.de
added Richard to this EMail, as maybe this could be a problem in linux too ... ?
drivers/mtd/ubi/wl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c index 507b091..e823ca5 100644 --- a/drivers/mtd/ubi/wl.c +++ b/drivers/mtd/ubi/wl.c @@ -1528,6 +1528,7 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) INIT_LIST_HEAD(&ubi->pq[i]); ubi->pq_head = 0;
- ubi->free_count = 0; list_for_each_entry_safe(aeb, tmp, &ai->erase, u.list) { cond_resched();
@@ -1546,7 +1547,6 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai) found_pebs++; }
- ubi->free_count = 0; list_for_each_entry(aeb, &ai->free, u.list) { cond_resched();