linux-kernel - Re: [RFC PATCH 2/2] serial: 8250

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1519407313.10722.127.camel@linux.intel.com>
Date:   Fri, 23 Feb 2018 19:35:13 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     John Garry <john.garry@...wei.com>, gregkh@...uxfoundation.org,
        slaby@...e.com, p.zabel@...gutronix.de, heiko@...ech.de,
        ed.blake@...drel.com, jhogan@...nel.org
Cc:     linux-serial@...r.kernel.org, linux-kernel@...r.kernel.org,
        linuxarm@...wei.com
Subject: Re: [RFC PATCH 2/2] serial: 8250_dw: support polling mode

On Fri, 2018-02-23 at 02:42 +0800, John Garry wrote:
> It would be useful to make this driver support some
> 8250-compatible devices which have no interrupt line.
> 
> For these, we allow for no interrupt, and will fallback on
> polling mode.
> 
> Note: the 8250 dt bindings state that "interrupts"
> is a required property:
> "interrupts : should contain uart interrupt."
> 
> But the 8250_of.c driver can live without it. So
> this patch is going this way also.

It should be documented in the binding.

>  	if (irq < 0) {
> -		if (irq != -EPROBE_DEFER)
> -			dev_err(dev, "cannot get irq\n");
> -		return irq;
> +		if (irq == -EPROBE_DEFER)
> +			return irq;
> +		dev_warn(dev, "cannot get irq, using polling
> mode\n");
> +		irq = 0;

NO_IRQ _is_ 0. You need to do something like

if (irq < 0) }
 ... leave existing code ...
}

if (!irq)
 dev_warn(, "Use polling mode\n");

-- 
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy