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From: Timur Tabi <timur@freescale.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: <kumar.gala@freescale.com>, <benh@kernel.crashing.org>,
	<greg@kroah.com>, <akpm@kernel.org>,
	<linuxppc-dev@lists.ozlabs.org>, <linux-kernel@vger.kernel.org>,
	<linux-console@vger.kernel.org>
Subject: Re: [PATCH 6/7] tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver
Date: Thu, 19 May 2011 10:09:16 -0500	[thread overview]
Message-ID: <4DD5329C.2040200@freescale.com> (raw)
In-Reply-To: <201105191702.39919.arnd@arndb.de>

Arnd Bergmann wrote:
> Why is this using a full tty driver instead of the hvc framework that most
> other hypervisor consoles use?

Because HVC uses the same interface for consoles and tty, and that resulted in
dropped characters if the client driver returns EAGAIN because it's output
buffer is full.  I posted a patch that "fixes" this, but it was rejected.
Here's the original patch:

http://lists.ozlabs.org/pipermail/linuxppc-dev/2010-August/085136.html

And here's the thread discussing our concerns:

http://lists.ozlabs.org/pipermail/linuxppc-dev/2010-September/thread.html

(search for "fix dropping of characters when output byte channel is full")

-- 
Timur Tabi
Linux kernel developer at Freescale


  reply	other threads:[~2011-05-19 15:09 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-19 13:54 [PATCH 0/7] This patchset adds support for running Linux under the Freescale hypervisor, Timur Tabi
2011-05-19 13:54 ` [PATCH 1/7] powerpc: make irq_choose_cpu() available to all PIC drivers Timur Tabi
2011-06-22 11:41   ` Kumar Gala
2011-05-19 13:54 ` [PATCH 2/7] powerpc: introduce ePAPR embedded hypervisor hcall interface Timur Tabi
2011-06-22 11:41   ` Kumar Gala
2011-05-19 13:54 ` [PATCH 3/7] powerpc: introduce the ePAPR embedded hypervisor vmpic driver Timur Tabi
2011-06-22 11:41   ` Kumar Gala
2011-05-19 13:54 ` [PATCH 4/7] powerpc: add Freescale hypervisor partition control functions Timur Tabi
2011-06-22 11:41   ` Kumar Gala
2011-05-19 13:54 ` [PATCH 5/7] powerpc/85xx: add board support for the Freescale hypervisor Timur Tabi
2011-06-22 11:42   ` Kumar Gala
2011-05-19 13:54 ` [PATCH 6/7] tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver Timur Tabi
2011-05-19 14:22   ` Greg KH
2011-05-19 14:27     ` Timur Tabi
2011-05-19 14:36     ` Alan Cox
2011-05-19 14:33   ` Alan Cox
2011-05-19 15:14     ` Timur Tabi
2011-05-19 15:50       ` Alan Cox
2011-05-19 15:54         ` Timur Tabi
2011-05-19 16:00           ` Alan Cox
2011-05-19 16:02           ` Greg KH
2011-05-19 16:18             ` Timur Tabi
2011-05-19 16:05     ` Timur Tabi
2011-05-20  9:54       ` Alan Cox
2011-05-19 16:31     ` Timur Tabi
2011-05-19 17:25       ` Alan Cox
2011-05-19 15:02   ` Arnd Bergmann
2011-05-19 15:09     ` Timur Tabi [this message]
2011-05-19 13:54 ` [PATCH 7/7] drivers/misc: introduce Freescale hypervisor management driver Timur Tabi
2011-05-19 13:56 ` [PATCH 0/7] This patchset adds support for running Linux under the Freescale hypervisor, Timur Tabi
2011-05-20 20:29 ` Kumar Gala
2011-05-23 21:09   ` Tabi Timur-B04825
2011-05-23 22:27     ` Kumar Gala

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