Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753109Ab0FWR2j (ORCPT ); Wed, 23 Jun 2010 13:28:39 -0400 Received: from ch-smtp03.sth.basefarm.net ([80.76.149.214]:49433 "EHLO ch-smtp03.sth.basefarm.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752914Ab0FWR2h (ORCPT ); Wed, 23 Jun 2010 13:28:37 -0400 Message-ID: <4C22441D.8000705@euromail.se> Date: Wed, 23 Jun 2010 19:27:57 +0200 From: Henrik Rydberg User-Agent: Thunderbird 2.0.0.24 (X11/20100411) MIME-Version: 1.0 To: Dmitry Torokhov CC: Ping Cheng , linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, Jiri Kosina , Ping Cheng , Benjamin Tissoires , Chase Douglas , Rafi Rubin Subject: Re: [PATCH 2/5] input: Use driver hint to compute the evdev buffer size (rev3) References: <1277291686-7153-1-git-send-email-rydberg@euromail.se> <1277291686-7153-2-git-send-email-rydberg@euromail.se> <1277291686-7153-3-git-send-email-rydberg@euromail.se> <4C223F60.6080904@euromail.se> <20100623171206.GA11512@core.coreip.homeip.net> In-Reply-To: <20100623171206.GA11512@core.coreip.homeip.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Originating-IP: 83.248.196.134 X-Scan-Result: No virus found in message 1ORTk0-0003eN-9l. X-Scan-Signature: ch-smtp03.sth.basefarm.net 1ORTk0-0003eN-9l ee2047e36988ebd925818413494e2106 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1737 Lines: 41 Dmitry Torokhov wrote: > On Wed, Jun 23, 2010 at 07:07:44PM +0200, Henrik Rydberg wrote: >> Hi Ping, >> [...] >>>> @@ -51,7 +52,9 @@ static DEFINE_MUTEX(evdev_table_mutex); >>>> >>>> static int evdev_compute_buffer_size(struct input_dev *dev) >>>> { >>>> - return EVDEV_MIN_BUFFER_SIZE; >>>> + int nev = dev->hint_events_per_packet * EVDEV_BUF_PACKETS; >>>> + nev = max(nev, EVDEV_MIN_BUFFER_SIZE); >>>> + return roundup_pow_of_two(nev); >>> I think we have a backward compatibility issue here. This routine will >>> return 7 when nev falls to the default value >>> (EVDEV_MIN_BUFFER_SIZE/64). This could happen to those drivers that >>> don't report MT events or forget/don't feel the need to set >>> hint_events_per_packet since the old BUFFER_SIZE worked perfectly for >>> them. We need to keep the return value for those drivers as 64 so we >>> could allocate the same space as it was in [PATCH 1/5]. >> Are you perhaps confusing EVDEV_BUF_PACKETS and EVDEV_MIN_BUFFER_SIZE? The last >> line ensures that the value returned is a power of two (hence not 7). The >> second-to-last line ensures the value is at least equal to 64 (hence not 7). The >> default hint value for a driver that does not do anything is zero, which leads >> to a return value of 64, just as it is today. >> > > I think Ping might have confused roundup_pow_of_two() with > get_order()-type function... > > Anyways, applied all 5, thanks Henrik. > Got them, thanks to you too. Henrik -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/