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From: "Francis Moreau" <francis.moro@gmail.com>
To: "Oliver Neukum" <oliver@neukum.org>
Cc: "David Brownell" <david-b@pacbell.net>,
	linux-usb@vger.kernel.org,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: usb_get_status(): what a weird implementation !
Date: Mon, 30 Jun 2008 16:03:52 +0200	[thread overview]
Message-ID: <38b2ab8a0806300703j7c0f0567w4cf1730fbe375c00@mail.gmail.com> (raw)
In-Reply-To: <200806301551.42252.oliver@neukum.org>

On Mon, Jun 30, 2008 at 3:51 PM, Oliver Neukum <oliver@neukum.org> wrote:
>
> If your buffer is smaller than CACHE_LINE_SIZE it should work.
> However, this needs input from people who understand DMA in and out.

yeah, that's the reason why it's a hack.

Maybe adding a new helper in  the dma API would be better...

> But how large is 2 * CACHE_LINE_SIZE compared to the kernel stack?

CACHE_LINE_SIZE = 32 bytes is common for embedded systems I guess.
For big system, I dunno.

Kernel stack size is usually  4KiB.

-- 
Francis

  reply	other threads:[~2008-06-30 14:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <200806261011.00287.oliver@neukum.org>
     [not found] ` <200806301346.11267.oliver@neukum.org>
     [not found]   ` <38b2ab8a0806300541q756e9b6fl445a5ee69d403ce7@mail.gmail.com>
2008-06-30 13:51     ` Oliver Neukum
2008-06-30 14:03       ` Francis Moreau [this message]
2008-06-30 14:11         ` Oliver Neukum
2008-06-30 14:22           ` Francis Moreau

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