From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267175AbUGMWdB (ORCPT ); Tue, 13 Jul 2004 18:33:01 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267179AbUGMWdA (ORCPT ); Tue, 13 Jul 2004 18:33:00 -0400 Received: from mustang.oldcity.dca.net ([216.158.38.3]:1753 "HELO mustang.oldcity.dca.net") by vger.kernel.org with SMTP id S267175AbUGMWcm (ORCPT ); Tue, 13 Jul 2004 18:32:42 -0400 Subject: Re: [linux-audio-dev] Re: [announce] [patch] Voluntary Kernel Preemption Patch From: Lee Revell To: Andrew Morton Cc: linux-audio-dev@music.columbia.edu, mingo@elte.hu, arjanv@redhat.com, linux-kernel@vger.kernel.org In-Reply-To: <20040713022919.67c991db.akpm@osdl.org> References: <20040709182638.GA11310@elte.hu> <20040710222510.0593f4a4.akpm@osdl.org> <1089673014.10777.42.camel@mindpipe> <20040712163141.31ef1ad6.akpm@osdl.org> <1089677823.10777.64.camel@mindpipe> <20040712174639.38c7cf48.akpm@osdl.org> <1089687168.10777.126.camel@mindpipe> <20040712205917.47d1d58b.akpm@osdl.org> <1089707483.20381.33.camel@mindpipe> <20040713014316.2ce9181d.akpm@osdl.org> <1089708818.20381.36.camel@mindpipe> <20040713020025.7400c648.akpm@osdl.org> <1089710638.20381.41.camel@mindpipe> <20040713022919.67c991db.akpm@osdl.org> Content-Type: text/plain Message-Id: <1089756594.3347.4.camel@mindpipe> Mime-Version: 1.0 X-Mailer: Ximian Evolution 1.4.6 Date: Tue, 13 Jul 2004 18:32:41 -0400 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2004-07-13 at 05:29, Andrew Morton wrote: > Lee Revell wrote: > > > > On Tue, 2004-07-13 at 05:00, Andrew Morton wrote: > > > Lee Revell wrote: > > > > > > > > > framebuffer scrolling inside lock_kernel(). Tricky. Suggest you use X or > > > > > vgacon. You can try removing the lock_kernel() calls from do_tty_write(), > > > > > but make sure you're wearing ear protection. > > > > > > > > > > > > > OK, I figured this was not an easy one. I can just not do that. > > > > > > Why not? You can certainly try removing those [un]lock_kernel() calls. > > > > > > > Maybe I missed something. What exactly do you mean by 'make sure you're > > wearing ear protection'? > > > > It might go boom. If it does screw up, it probably won't be very seriously > bad - maybe some display glitches. Just an experiment. > - > 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/ > Seems to work perfectly. No visible display glitches. I would imagine that putting a modem on a tty, then stressing the system and watching for line errors would be a definitive test. --- drivers/char/tty_io.c.orig 2004-07-13 16:55:28.000000000 -0400 +++ drivers/char/tty_io.c 2004-07-13 16:55:51.000000000 -0400 @@ -684,17 +684,13 @@ return -ERESTARTSYS; } if ( test_bit(TTY_NO_WRITE_SPLIT, &tty->flags) ) { - lock_kernel(); written = write(tty, file, buf, count); - unlock_kernel(); } else { for (;;) { unsigned long size = max((unsigned long)PAGE_SIZE*2, 16384UL); if (size > count) size = count; - lock_kernel(); ret = write(tty, file, buf, size); - unlock_kernel(); if (ret <= 0) break; written += ret; Lee