From: Ed Blake <ed.blake@sondrel.com>
To: "Nuno Gonçalves" <nunojpg@gmail.com>
Cc: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
linux-serial@vger.kernel.org
Subject: Re: [PATCH] 8250_dw: do not int overflow when rate can not be aplied
Date: Fri, 12 Jan 2018 13:33:22 +0000 [thread overview]
Message-ID: <48ee75ee-2d3a-c299-4ed8-23eb9ea27666@sondrel.com> (raw)
In-Reply-To: <4fc98be4-e489-20f0-d899-e5eabdbd5e9d@sondrel.com>
On 11/01/18 18:03, Ed Blake wrote:
> On 11/01/18 17:55, Nuno Gonçalves wrote:
>> So, for me clk_round_rate() always returns 24000000, and only the loop
>> variable i changes, so the search is monotonic, from the highest baud
>> to the lowest (increasing divider).
>>
>> I am using a Allwiner H2+, with the serial port configuration from
>> sunxi-h3-h5.dtsi.
>>
>> Are you sure that clk_round_rate can return differet values? Is that
>> because some boards might have several clock options beside the
>> adjustable divider?
> Yes I'm sure. Some platforms allow the clock rate to be varied, hence
> the existence of clk_round_rate() and clk_set_rate().
>
>> I really need to understand what is the problem, to be able to suggest
>> a solution to the integer overflow that is being allowed to happen.
> Some sort of overflow check on i * max_rate could work?
Actually I have another suggestion. I'll submit a separate patch.
--
Ed
prev parent reply other threads:[~2018-01-12 13:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-11 13:38 [PATCH] 8250_dw: do not int overflow when rate can not be aplied Nuno Goncalves
2018-01-11 17:18 ` Ed Blake
2018-01-11 17:28 ` Nuno Gonçalves
2018-01-11 17:48 ` Ed Blake
2018-01-11 17:55 ` Nuno Gonçalves
2018-01-11 18:03 ` Ed Blake
2018-01-12 13:33 ` Ed Blake [this message]
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