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
| ||
|
Date: Thu, 23 Oct 2014 14:10:19 +0900 From: Alexandre Courbot <gnurou@...il.com> To: Octavian Purdila <octavian.purdila@...el.com> Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Linus Walleij <linus.walleij@...aro.org>, Wolfram Sang <wsa@...-dreams.de>, Samuel Ortiz <sameo@...ux.intel.com>, Lee Jones <lee.jones@...aro.org>, Arnd Bergmann <arnd@...db.de>, Johan Hovold <johan@...nel.org>, Daniel Baluta <daniel.baluta@...el.com>, Laurentiu Palcu <laurentiu.palcu@...el.com>, "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>, Linux Kernel Mailing List <linux-kernel@...r.kernel.org>, "linux-gpio@...r.kernel.org" <linux-gpio@...r.kernel.org>, "linux-i2c@...r.kernel.org" <linux-i2c@...r.kernel.org> Subject: Re: [PATCH v8 3/4] gpiolib: add irq_not_threaded flag to gpio_chip On Mon, Oct 20, 2014 at 7:19 PM, Octavian Purdila <octavian.purdila@...el.com> wrote: > On Mon, Oct 20, 2014 at 8:08 AM, Alexandre Courbot <gnurou@...il.com> wrote: >> >> On Wed, Oct 15, 2014 at 11:48 PM, Octavian Purdila >> <octavian.purdila@...el.com> wrote: >> > Some GPIO chips (e.g. the DLN2 USB adapter) have blocking get/set >> > operation but do not need a threaded irq handler. >> >> Sorry if you already explained this (I have been a little bit late >> with the GPIO reviews recently), but does this optimization bring a >> significant benefit that justifies adding another field in struct >> gpio_chip? If so it would be nice to have it in the commit message. If >> not, do we need this at all? > > Hi Alexandre, > > In the case DLN2 USB GPIO adapter the GPIO interrupt is generated in > the completion routine of a receive URB, which means that we are in > interrupt context. If a threaded irq is used, we would have to > schedule work instead of running to interrupt handler directly which > is unnecessary and adds latency. > > BTW, AFAIC Linus W already merged this patch in his next tree, I am > keeping it in this series because it was not pulled in the mfd-next > tree. You're right, it's all good then. Thanks for the explanation. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists