From mboxrd@z Thu Jan 1 00:00:00 1970 X-GM-THRID: 6669793876600946688 X-Received: by 2002:aca:5115:: with SMTP id f21mr7013639oib.50.1552934744316; Mon, 18 Mar 2019 11:45:44 -0700 (PDT) X-BeenThere: outreachy-kernel@googlegroups.com Received: by 2002:aca:be04:: with SMTP id o4ls53513oif.1.gmail; Mon, 18 Mar 2019 11:45:43 -0700 (PDT) X-Google-Smtp-Source: APXvYqyhvdB0RYuNE3FPArEVBiojuI5+PLN995kQeF8Z1l0FLWB2wJaAriUd+Yd78CMKhDzRtsQR X-Received: by 2002:aca:c6c8:: with SMTP id w191mr1740191oif.24.1552934743379; Mon, 18 Mar 2019 11:45:43 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1552934743; cv=none; d=google.com; s=arc-20160816; b=RdviE5xsDuvpWS2hioCY0iQutDrTzk9wnD/Optkrno7ONvXV1+zfTx7+6QJKk9lFma qv8ftJeJkXnunJ0nCtRQG98runaYwWxUh0szcOLlX+1Tl326PHONUg4RqpRUuTma8gfm XskBs6/+R+dD36tg2fR9+g7LTyFUnYD8qLjPiTtIVAoT8mbCw1n0yE6PyK3K2xhdiAAl WUn3mmEoejMgh3AemzCggpPbqA+Iajsy7VtFDTQcqrNqDsfU8/diouMhqiBXLavFhIei XsSbVVoY/Qzq5XqQ85ezDsPCI0QCMk/WeSCbCMv/+v1xxfF4RrijhSm7NJbmYCi6m1TE GHiw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=user-agent:in-reply-to:content-disposition:mime-version:references :message-id:subject:cc:to:from:date:dkim-signature; bh=jYu7EMGcQtEaknQVfJ+8S0Jj5XT4d8p+i+aHpxAHQAM=; b=dxZdwDGiOJKCYNnIWiu0tX4qW2zHdIkGA7KT3tTx8U0BJrxdjNn0Y6dRKaZb+l76ja w46qMzX+dTN1IMaKLkWfH7p+k141PErFq0SwlqsOFmzZ919HhRLlQjf6RXKZdJfd/l1S uOeJnZiBU2h03iLOyzhSficljBuvin/dU3Qzthg9PYXjGOcL1Kt+OeTLy9Za5E2kqliY VBXuw+2unHNgPGvIDeHGY/olF4luO/l+H4cJt/AD6hrdNkznKY74tjGLSFkcmMeVRMbp n3IBX/X5cxFlozVmYCqji32DIijRCpo4VvUMfpZCat9i6aGaGtNXbDtaaIgZW0ar/8oZ /Baw== ARC-Authentication-Results: i=1; gmr-mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=czwja9JO; spf=pass (google.com: domain of gregkh@linuxfoundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Return-Path: Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by gmr-mx.google.com with ESMTPS id u185si426145oib.2.2019.03.18.11.45.43 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 18 Mar 2019 11:45:43 -0700 (PDT) Received-SPF: pass (google.com: domain of gregkh@linuxfoundation.org designates 198.145.29.99 as permitted sender) client-ip=198.145.29.99; Authentication-Results: gmr-mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=czwja9JO; spf=pass (google.com: domain of gregkh@linuxfoundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 000122077B; Mon, 18 Mar 2019 18:45:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1552934742; bh=Mw49IXXoNK/xYeBY5lbqTPyx/51v4n3YccSD66o2Hik=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=czwja9JOLloIOS7Ed9dHnLqZ4k+WcvDwedoZDFCjQhDfaU3LqwK2fA2V45uW3ot8L lbwQ5Er38JAVmA3sgfUgid8MFenONbKUQl+qssl1TMJucZcCpv85PMmR3lt4eJKWVZ rQVJsIZKUtbky7gFldFtWAJZnMEIaGD82K4K+38Y= Date: Mon, 18 Mar 2019 19:45:39 +0100 From: Greg KH To: Payal Kshirsagar Cc: outreachy-kernel@googlegroups.com Subject: Re: [PATCH] [Outreachy kernel] staging: speakup: prefer usleep_range over udelay Message-ID: <20190318184539.GA11680@kroah.com> References: <1552932384-11028-1-git-send-email-payal.s.kshirsagar.98@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1552932384-11028-1-git-send-email-payal.s.kshirsagar.98@gmail.com> User-Agent: Mutt/1.11.4 (2019-03-13) On Mon, Mar 18, 2019 at 11:36:24PM +0530, Payal Kshirsagar wrote: > Since usleep_range is built on top of hrtimers, the > wakeup will be very precise (ish), thus a simple > usleep function would likely introduce a large number > of undesired interrupts. > Thus udelay replaced with usleep_range. > > Signed-off-by: Payal Kshirsagar > --- > drivers/staging/speakup/speakup_decpc.c | 14 +++++++------- > 1 file changed, 7 insertions(+), 7 deletions(-) > > diff --git a/drivers/staging/speakup/speakup_decpc.c b/drivers/staging/speakup/speakup_decpc.c > index 798c42d..10ca19b 100644 > --- a/drivers/staging/speakup/speakup_decpc.c > +++ b/drivers/staging/speakup/speakup_decpc.c > @@ -251,7 +251,7 @@ static int dt_waitbit(int bit) > while (--timeout > 0) { > if ((dt_getstatus() & bit) == bit) > return 1; > - udelay(50); > + usleep_range(50, 50 + 10); I've said this in the past, only do this type of change if you can actually test it, and know it will be ok. For some stuff like this, it _might_ be ok, but you just expanded the timeout range potentially a lot longer than before, and do we know that is ok? I sure do not :) So just leave these things alone unless you know the hardware will keep working properly. thanks, greg k-h