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* Preparation for sync with Linus.
@ 2001-09-19 22:49 David Woodhouse
  2001-09-20  9:39 ` Jarkko Lavinen
  0 siblings, 1 reply; 3+ messages in thread
From: David Woodhouse @ 2001-09-19 22:49 UTC (permalink / raw)
  To: linux-mtd

I'm preparing to send the latest code to Linus. I'm going to read through 
the patch for obvious bogosity, probably removing some of the changes which 
are only for portability, and do some basic testing tomorrow. 

In the meantime, if there's anything you don't like about the current set 
of changes, now would be a good time to shout.

ftp.uk.linux.org:/pub/people/dwmw2/mtd/mtd-diff-against-2.4.9-pre12-v9

--
dwmw2

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Preparation for sync with Linus.
  2001-09-19 22:49 Preparation for sync with Linus David Woodhouse
@ 2001-09-20  9:39 ` Jarkko Lavinen
  2001-09-20  9:58   ` David Woodhouse
  0 siblings, 1 reply; 3+ messages in thread
From: Jarkko Lavinen @ 2001-09-20  9:39 UTC (permalink / raw)
  To: MTD List; +Cc: David Woodhouse

> In the meantime, if there's anything you don't like about the current set 
> of changes, now would be a good time to shout.

Hi David,

if the chip has sectors locked after cold boot, currently I have to either 
run unlock command or add a call to unlock function into the map driver.

Should chip driver unlock sectors if chip is detected and the sectors are 
suspected to be locked?

Jarkko Lavinen

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: Preparation for sync with Linus.
  2001-09-20  9:39 ` Jarkko Lavinen
@ 2001-09-20  9:58   ` David Woodhouse
  0 siblings, 0 replies; 3+ messages in thread
From: David Woodhouse @ 2001-09-20  9:58 UTC (permalink / raw)
  To: Jarkko Lavinen; +Cc: MTD List

jlavi@iki.fi said:
>  if the chip has sectors locked after cold boot, currently I have to
> either  run unlock command or add a call to unlock function into the
> map driver.

> Should chip driver unlock sectors if chip is detected and the sectors
> are  suspected to be locked? 

There are two possible types of mishap which the locking can protect us 
from:

1. Kernel bugs where misdirected memory accesses could write to or erase
	parts of the flash.
2. User error leading to the erasure of important flash partitions, like
	mounting the boot loader partition as JFFS2.

If we care primarily about #1, we should keep the sectors locked at all 
times and unlock them only when we want to access them. 

If we care primarily about #2, then we should unlock sectors _only_ when 
explicitly requested to do so by the user.

I think that the facility to switch Vpp off while the chip is idle, coupled
with the complexity of the sequence of writes necessary to actually write to
a flash chip, makes it unlikely that #1 is a serious concern - so we
currently unlock sectors only when explicitly requested to do so by the
user.

--
dwmw2

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2001-09-20  9:53 UTC | newest]

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2001-09-19 22:49 Preparation for sync with Linus David Woodhouse
2001-09-20  9:39 ` Jarkko Lavinen
2001-09-20  9:58   ` David Woodhouse

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