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From: sylvain.rochet@finsecur•com (Sylvain Rochet)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] USB: gadget: atmel_usba_udc: Enable/disable USB PLL on Vbus change
Date: Sat, 17 Jan 2015 12:07:10 +0100	[thread overview]
Message-ID: <20150117110710.GB24176@gradator.net> (raw)
In-Reply-To: <20150117104358.0282b27f@bbrezillon>

Hello Boris,

On Sat, Jan 17, 2015 at 10:43:58AM +0100, Boris Brezillon wrote:
> 
> You're right, except that calling enable/disable on the PLL clk in irq
> context is pretty much useless since the activation/deactivation code
> of the PLL is in prepare/unprepare, so you won't save much power by
> doing that (gating the peripheral clk should save a bit though). 
> 
> To solve that issue I thought we could move to a threaded_irq (where we
> can safely sleep), but you'll also have to take of not calling
> prepare/unprepare in sections where at least one spinlock is taken (for
> the same reason => you cannot sleep with while you hold spinlocks).

Hummm, I must admit I waited for such a useful tip, adding the 
prepare/unprepare in interrupt context looked dirty at first sight, 
thank you very much :)

I will try with a threaded_irq.

Sylvain

  reply	other threads:[~2015-01-17 11:07 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-16 22:21 [PATCH] USB: gadget: atmel_usba_udc: Enable/disable USB PLL on Vbus change Sylvain Rochet
2015-01-17  1:42 ` Alexandre Belloni
2015-01-17  9:43   ` Boris Brezillon
2015-01-17 11:07     ` Sylvain Rochet [this message]
2015-01-18 14:51       ` [PATCHv2 0/2] " Sylvain Rochet
2015-01-18 14:51         ` [PATCHv2 1/2] USB: gadget: atmel_usba_udc: Fixed vbus_prev initial state Sylvain Rochet
2015-01-18 14:51         ` [PATCH 2/2] USB: gadget: atmel_usba_udc: Enable/disable USB PLL on Vbus change Sylvain Rochet
2015-01-18 16:56           ` Boris Brezillon
2015-01-18 17:24             ` [PATCHv3 0/2] " Sylvain Rochet
2015-01-18 17:24               ` [PATCHv3 1/2] USB: gadget: atmel_usba_udc: Fixed vbus_prev initial state Sylvain Rochet
2015-01-19 14:09                 ` Nicolas Ferre
2015-01-19 18:55                   ` Felipe Balbi
2015-01-20 11:02                     ` Sylvain Rochet
2015-01-20 11:11                       ` Nicolas Ferre
2015-01-18 17:24               ` [PATCHv3 2/2] USB: gadget: atmel_usba_udc: Enable/disable USB PLL on Vbus change Sylvain Rochet
2015-01-19 16:55                 ` Nicolas Ferre
2015-01-19 17:46                   ` Sylvain Rochet
2015-01-19 20:15                     ` Boris Brezillon
2015-01-20  9:02                       ` Nicolas Ferre
2015-01-18 17:34           ` [PATCH " Boris Brezillon

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