From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-lb0-x232.google.com ([2a00:1450:4010:c04::232]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Zjruy-0007AL-4B for barebox@lists.infradead.org; Wed, 07 Oct 2015 16:50:17 +0000 Received: by lbcao8 with SMTP id ao8so18711511lbc.3 for ; Wed, 07 Oct 2015 09:49:54 -0700 (PDT) Date: Wed, 7 Oct 2015 19:52:21 +0300 From: Peter Mamonov Message-ID: <20151007195221.7aaea4c6@berta> In-Reply-To: <20151007154024.GA14384@ns203013.ovh.net> References: <1442937514-19675-1-git-send-email-pmamonov@gmail.com> <1442937514-19675-5-git-send-email-pmamonov@gmail.com> <20151007134703.GA8288@ns203013.ovh.net> <20151007174016.00ac1be5@berta> <20151007154024.GA14384@ns203013.ovh.net> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: [PATCH 4/5] usb: ehci-hcd: use mdelay_non_inerruptible() To: Jean-Christophe PLAGNIOL-VILLARD Cc: barebox@lists.infradead.org On Wed, 7 Oct 2015 17:40:24 +0200 Jean-Christophe PLAGNIOL-VILLARD wrote: > On 17:40 Wed 07 Oct , Peter Mamonov wrote: > > On Wed, 7 Oct 2015 15:47:03 +0200 > > Jean-Christophe PLAGNIOL-VILLARD wrote: > > > > > On 18:58 Tue 22 Sep , Peter Mamonov wrote: > > > > Signed-off-by: Peter Mamonov > > > > --- > > > > drivers/usb/host/ehci-hcd.c | 6 +++--- > > > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/drivers/usb/host/ehci-hcd.c > > > > b/drivers/usb/host/ehci-hcd.c index d6df7b8..03d6150 100644 > > > > --- a/drivers/usb/host/ehci-hcd.c > > > > +++ b/drivers/usb/host/ehci-hcd.c > > > > @@ -684,7 +684,7 @@ ehci_submit_root(struct usb_device *dev, > > > > unsigned long pipe, void *buffer, > > > > * root > > > > */ > > > > ehci_powerup_fixup(ehci); > > > > - mdelay(50); > > > > + mdelay_non_interruptible(50); > > > > ehci->portreset |= 1 << port; > > > > /* terminate the reset */ > > > > ehci_writel(status_reg, reg & > > > > ~EHCI_PS_PR); @@ -747,7 +747,7 @@ ehci_submit_root(struct > > > > usb_device *dev, unsigned long pipe, void *buffer, goto unknown; > > > > } > > > > > > > > - mdelay(1); > > > > + mdelay_non_interruptible(1); > > > > len = min3(srclen, (int)le16_to_cpu(req->length), > > > > length); if (srcptr != NULL && len > 0) > > > > memcpy(buffer, srcptr, len); > > > > @@ -889,7 +889,7 @@ static int ehci_init(struct usb_host *host) > > > > ehci_writel(&ehci->hcor->or_configflag, cmd); > > > > /* unblock posted write */ > > > > cmd = ehci_readl(&ehci->hcor->or_usbcmd); > > > > - mdelay(5); > > > > + mdelay_non_interruptible(5); > > > why do you need that much non interruptible delau? > > > > Non-interruptible delays are needed here to prevent ehci_* functions > > re-entrance. The re-entrance occurs during a usb bus scan, after > > detection of a usb keyboard. As soon as a USB keyboard is detected, > > it's driver starts the poller, which interferes with the process of > > usb bus scan. However that last one delay may be interruptible. > > my problem is as soon as you start a usb control msg you block > everything > > nothing else can run in barebox > > can slow down barebox boot > > I do think we need a real mdelay_non_interruptible feature but just > forbidden to recall usb control msg. > But the rest of barebox can run durring those 5ms Well, I think it can be done by returning -EAGAIN on re-entrance detection in ehci_* functions [1], and skipping the poll in the keyboard driver. By the way, could you clarify: do you really experience considerable barebox slowdown or you make an assumtion based on the code analysis? [1] http://lists.infradead.org/pipermail/barebox/2015-September/024715.html Regards, Peter > > Best Regards, > J. _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox