linux-kernel - Re: [PATCH v2 05/10] mtd: rawnand: denali: use more precise timeout for NAND_OP_WAITRDT_INSTR

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Date:   Tue, 5 Mar 2019 15:36:24 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     Boris Brezillon <bbrezillon@...nel.org>,
        Richard Weinberger <richard@....at>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Marek Vasut <marek.vasut@...il.com>,
        linux-mtd <linux-mtd@...ts.infradead.org>,
        Brian Norris <computersforpeace@...il.com>,
        David Woodhouse <dwmw2@...radead.org>
Subject: Re: [PATCH v2 05/10] mtd: rawnand: denali: use more precise timeout
 for NAND_OP_WAITRDT_INSTR

Hi Miquel,

On Mon, Mar 4, 2019 at 5:44 PM Miquel Raynal <miquel.raynal@...tlin.com> wrote:
>
> Hi Masahiro,
>
> Masahiro Yamada <yamada.masahiro@...ionext.com> wrote on Tue, 12 Feb
> 2019 16:12:57 +0900:
>
> > Currently, wait_for_completion_timeout() is always passed in the
> > hard-coded msec_to_jiffies(1000). There is no specific reason for
> > 1000 msec, but it was chosen to be long enough.
> >
> > With the exec_op() conversion, NAND_OP_WAITRDY_INSTR provides more
> > precise timeout value, depending on the preceding command. Let's use
> > it (+ 100 msec) to bail out earlier in error case. The 100 msec extra
> > is in case the heavy load on the system.
> >
> > I am still keeping the hard-coded values for other higher level hooks
> > such as page_read, page_write, etc. We know the value of tR, tPROG, but
> > we have unknowledge about the data transfer speed of the DMA engine.
> >
> > Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
>
> I really am not convinced by this change. Please just define a timeout
> big enough for most cases (1000 is okay) and use it systematically.

OK, I will drop this patch.
and ignore ctx.waitrdy.timeout_ms.

> Thanks,
> Miquèl
>
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/

--
Best Regards
Masahiro Yamada

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