Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Sun, 17 Dec 2000 08:03:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Sun, 17 Dec 2000 08:03:10 -0500 Received: from host154.207-175-42.redhat.com ([207.175.42.154]:9630 "EHLO lacrosse.corp.redhat.com") by vger.kernel.org with ESMTP id ; Sun, 17 Dec 2000 08:03:04 -0500 Date: Sun, 17 Dec 2000 12:32:37 +0000 From: Tim Waugh To: Linus Torvalds Cc: linux-kernel@vger.kernel.org Subject: [patch] 2.4.0-test13-pre2: better parport_pc commentary Message-ID: <20001217123237.F19671@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Linus, Here is a patch to make the parport_pc comments better. No code change. Tim. */ 2000-12-17 Tim Waugh * drivers/parport/parport_pc.c: Better commentary. Patch from R Horn. * drivers/parport/ChangeLog: Updated. --- linux-2.4.0-test12/drivers/parport/parport_pc.c.commentary Tue Dec 12 13:03:24 2000 +++ linux-2.4.0-test12/drivers/parport/parport_pc.c Wed Dec 13 14:11:11 2000 @@ -938,13 +938,11 @@ /* Can't yield the port. */ schedule (); - /* At this point, the FIFO may already be full. - * Ideally, we'd be able to tell the port to hold on - * for a second while we empty the FIFO, and we'd be - * able to ensure that no data is lost. I'm not sure - * that's the case. :-( It might be that you can play - * games with STB, as in the forward case; someone should - * look at a datasheet. */ + /* At this point, the FIFO may already be full. In + * that case ECP is already holding back the + * peripheral (assuming proper design) with a delayed + * handshake. Work fast to avoid a peripheral + * timeout. */ if (ecrval & 0x01) { /* FIFO is empty. Wait for interrupt. */ @@ -976,6 +974,10 @@ goto false_alarm; } + /* Depending on how the FIFO threshold was + * set, how long interrupt service took, and + * how fast the peripheral is, we might be + * lucky and have a just filled FIFO. */ continue; } @@ -987,6 +989,9 @@ continue; } + /* FIFO not filled. We will cycle this loop for a while + * and either the peripheral will fill it faster, + * tripping a fast empty with insb, or we empty it. */ *bufp++ = inb (fifo); left--; } --- linux-2.4.0-test12/drivers/parport/ChangeLog.commentary Wed Dec 13 14:17:10 2000 +++ linux-2.4.0-test12/drivers/parport/ChangeLog Wed Dec 13 14:17:26 2000 @@ -0,0 +1,4 @@ +2000-12-17 R Horn + + * parport_pc.c: Some commentary changes. + - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/