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Date: Tue, 28 Jun 2011 17:09:29 +0200
From: Matthieu CASTET <matthieu.castet@parrot.com>
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Subject: Re: [PATCH 1/6] nand_wait_ready timeout fix
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Artem Bityutskiy a écrit :
> On Sun, 2011-06-26 at 18:26 +0200, Matthieu CASTET wrote:
>> nand_wait_ready timeout should not assume HZ=1000.
>> Make it independent of HZ value.
>>
>> Signed-off-by: Matthieu CASTET <matthieu.castet@parrot.com>
>> ---
>>  drivers/mtd/nand/nand_base.c |    2 +-
>>  1 files changed, 1 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/mtd/nand/nand_base.c b/drivers/mtd/nand/nand_base.c
>> index a46e9bb..a3c7fd3 100644
>> --- a/drivers/mtd/nand/nand_base.c
>> +++ b/drivers/mtd/nand/nand_base.c
>> @@ -512,7 +512,7 @@ static void panic_nand_wait_ready(struct mtd_info *mtd, unsigned long timeo)
>>  void nand_wait_ready(struct mtd_info *mtd)
>>  {
>>  	struct nand_chip *chip = mtd->priv;
>> -	unsigned long timeo = jiffies + 2;
>> +	unsigned long timeo = jiffies + (2 * HZ) / 1000;
> 
> I agree that the code is buggy, but your fix is strange: if HZ = 100, (2
> * HZ) / 1000 will be zero?
> 
> I think you should instead know for how many msecs you want to wait, and
> use msecs_to_jiffies().
> 
Your right, I assume the code was written for HZ=100, and the code should wait
for 20 ms :
unsigned long timeo = jiffies + (20 * HZ) / 1000;

this will match with the
static int nand_wait(struct mtd_info *mtd, struct nand_chip *chip)
{

    unsigned long timeo = jiffies;
    int status, state = chip->state;

    if (state == FL_ERASING)
        timeo += (HZ * 400) / 1000;
    else
        timeo += (HZ * 20) / 1000;
[...]
}

Matthieu