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<tt>Hello David,<br>
<br>
Thank you for your response! <br>
<br>
Your answer makes sense for me. In this case it would be useful to
refactor the "backupless" writes to read sectors only until a non
0xFF portion found, and then mark that sector erasable or erase
immediately. In the case if the flash has non blank region this
could speed up the programming, worst case (programming a fully
erased chip) it is going to be equal in time.<br>
<br>
I have not been aware of Nico's patch. Is it already merged to the
mainline? If not could you please give me a link to that?<br>
Thank you!<br>
<br>
</tt>
<pre class="moz-signature" cols="72">Regards,
Miklos Marton
</pre>
<div class="moz-cite-prefix">2015-12-11 21:52 keltezéssel, David
Hendricks írta:<br>
</div>
<blockquote
cite="mid:CAKOoyUcjJ31mOHS+jCryg3xrSey467mRFycRnddDVKN7Edt7Nw@mail.gmail.com"
type="cite">
<div dir="ltr">Hi Marton,
<div>I respectfully disagree with this approach. Reading the old
contents is not just used for backup. It's used so that
flashrom can selectively erase and write blocks which usually
saves time because erase and write operations are orders of
magnitude slower than reads on NOR flash.</div>
<div><br>
</div>
<div>So, it's not a bad thing to support this option, but I
think there is little benefit and can actually make the
process slower in most cases. (Your case might be different,
of course)</div>
<div><br>
</div>
<div>Nico Huber's unbounded read patch should help reduce the
initial read time by a large factor (~90% reduction). Try
marking your chip as tested for unbounded reads. You might
find that the read and selective erase/write is faster than
unconditional erase/write.<br>
</div>
<div><br>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Dec 11, 2015 at 12:01 PM,
Márton Miklós <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:martonmiklosqdev@gmail.com" target="_blank">martonmiklosqdev@gmail.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> <tt>Hello all,<br>
<br>
I am using the flashrom with an external programmer to
flash various SPI flashes a lot.<br>
In most cases I do not care about the old flash contents
when flashing, so the "</tt><tt><i><tt>Reading old flash
chip contents</tt></i>" step does not have any added
value in my use cases. The code also has a FIXME note
where this is hardcoded to make it configurable in the
future. I would like to patch it if possible. <br>
<br>
Please propose me command line arguments for disabling
it. My proposal:<br>
<i>-N | --nobackup skip reading back old flash contents
before write</i><br>
<br>
I know -N could be confused with -n but the same applies
to the -v (verify) and -V (verbose).<br>
I also could live without the short argument, but that
would break the "standard".<br>
<br>
Thanks in advance for your feedback!<span class="HOEnZb"><font
color="#888888"><br>
</font></span></tt><span class="HOEnZb"><font
color="#888888">
<pre cols="72">--
Regards,
Miklos Marton
</pre>
</font></span></div>
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</blockquote>
</div>
<br>
<br clear="all">
<div><br>
</div>
-- <br>
<div class="gmail_signature">David Hendricks (dhendrix)<br>
Systems Software Engineer, Google Inc.</div>
</div>
</blockquote>
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