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From: Felipe Balbi <felipe.balbi-xNZwKgViW5gAvxtiuMwx3w@public.gmane.org>
To: "ext Gupta, Ajay Kumar" <ajay.gupta-l0cyMroinI0@public.gmane.org>
Cc: "me-uiRdBs8odbtmTBlB0Cgj/Q@public.gmane.org"
	<me-uiRdBs8odbtmTBlB0Cgj/Q@public.gmane.org>,
	"linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	"linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org"
	<linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
Subject: Re: [PATCH 4/5] musb: use system DMA for unaligned buffers on RTL >= 1.8
Date: Fri, 14 May 2010 14:06:48 +0300	[thread overview]
Message-ID: <20100514110648.GA3947@nokia.com> (raw)
In-Reply-To: <19F8576C6E063C45BE387C64729E7394044E405169-/tLxBxkBPtCIQmiDNMet8wC/G2K4zDHf@public.gmane.org>

On Thu, May 13, 2010 at 06:13:00AM +0200, ext Gupta, Ajay Kumar wrote:
>How about this 'memcpy', this would affect both cpu loading
>and performance. That's why using system dma would be a better
>approach.

but that's not portable. Even if you come up with nice wrappers for 
system dma usage (which is already ugly, more exported functions) you 
might end up on a board where system dma has same alignment constraints 
as mentor dma. Either fall back to pio or use a bounce buffer. That'll 
work always.

Besides, the only offending gadget driver we have is g_ether and that's 
already 'fixed' by the alignment patch to g_ether. Any other gadget 
driver causing that, should be fixed too...

-- 
balbi

DefectiveByDesign.org
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  parent reply	other threads:[~2010-05-14 11:06 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-05-12 11:49 [PATCH 1/5] musb: save OTG base physical address Ajay Kumar Gupta
2010-05-12 11:49 ` [PATCH 2/5] musb: use system DMA to fix Inventra DMA issue on RTL-1.4 Ajay Kumar Gupta
     [not found]   ` <1273664979-493-2-git-send-email-ajay.gupta-l0cyMroinI0@public.gmane.org>
2010-05-12 11:49     ` [PATCH 3/5] musb: add function to check if Inventra DMA used Ajay Kumar Gupta
     [not found]       ` <1273664979-493-3-git-send-email-ajay.gupta-l0cyMroinI0@public.gmane.org>
2010-05-12 11:49         ` [PATCH 4/5] musb: use system DMA for unaligned buffers on RTL >= 1.8 Ajay Kumar Gupta
     [not found]           ` <1273664979-493-4-git-send-email-ajay.gupta-l0cyMroinI0@public.gmane.org>
2010-05-12 11:49             ` [PATCH 5/5] musb: dma: use optimal transfer element for sdma Ajay Kumar Gupta
2010-05-12 13:18             ` [PATCH 4/5] musb: use system DMA for unaligned buffers on RTL >= 1.8 Sergei Shtylyov
2010-05-12 13:55               ` Gupta, Ajay Kumar
2010-05-12 14:59                 ` Sergei Shtylyov
     [not found]                   ` <4BEAC268.1080601-hkdhdckH98+B+jHODAdFcQ@public.gmane.org>
2010-05-12 17:55                     ` Felipe Balbi
2010-05-13  4:14                       ` Gupta, Ajay Kumar
     [not found]                         ` <19F8576C6E063C45BE387C64729E7394044E40516A-/tLxBxkBPtCIQmiDNMet8wC/G2K4zDHf@public.gmane.org>
2010-05-13 19:43                           ` Felipe Balbi
2010-05-14  4:39                             ` Gupta, Ajay Kumar
2010-05-12 17:54             ` Felipe Balbi
2010-05-13  4:13               ` Gupta, Ajay Kumar
     [not found]                 ` <19F8576C6E063C45BE387C64729E7394044E405169-/tLxBxkBPtCIQmiDNMet8wC/G2K4zDHf@public.gmane.org>
2010-05-14 11:06                   ` Felipe Balbi [this message]
2010-05-14 11:39                     ` Gupta, Ajay Kumar
2010-05-12 17:52       ` [PATCH 3/5] musb: add function to check if Inventra DMA used Felipe Balbi
2010-05-12 17:51     ` [PATCH 2/5] musb: use system DMA to fix Inventra DMA issue on RTL-1.4 Felipe Balbi
2010-05-12 17:56       ` Gadiyar, Anand
     [not found]         ` <5A47E75E594F054BAF48C5E4FC4B92AB03216237DA-/tLxBxkBPtCIQmiDNMet8wC/G2K4zDHf@public.gmane.org>
2010-05-13  4:22           ` Gupta, Ajay Kumar
2010-05-13  8:58             ` Kalliguddi, Hema
2010-05-13 10:10               ` Gupta, Ajay Kumar
2010-05-13 11:57                 ` Kalliguddi, Hema

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