From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 3 Jan 2001 19:10:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 3 Jan 2001 19:10:31 -0500 Received: from fep03.swip.net ([130.244.199.131]:37335 "EHLO fep03-svc.swip.net") by vger.kernel.org with ESMTP id ; Wed, 3 Jan 2001 19:10:18 -0500 To: Andrea Arcangeli Cc: linux-kernel@vger.kernel.org, linux-parport@torque.net, tim@cyberelk.demon.co.uk Subject: Re: Printing to off-line printer in 2.4.0-prerelease In-Reply-To: <20010103201344.A3203@athlon.random> <20010103223504.L32185@athlon.random> From: Peter Osterlund Date: 04 Jan 2001 01:08:01 +0100 In-Reply-To: Andrea Arcangeli's message of "Wed, 3 Jan 2001 22:35:04 +0100" Message-ID: X-Mailer: Gnus v5.7/Emacs 20.7 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrea Arcangeli writes: > On Wed, Jan 03, 2001 at 10:00:59PM +0100, Peter Osterlund wrote: > > off. Apparently the printer tells the computer it is OK to send data > > to it when it is off. > > So then parport_write is probably buggy because it's losing data silenty while > the printer is off. So the below is probably a band aid. Really some printer > acts in a different way (see the LP_CAREFUL hack in 2.2.x) so it maybe that > parport_write is ok on some printer and it would need something like a > LP_CAREFUL option to work also on some other printer. Or maybe some parport > handshake is badly designed in hardware and it cannot report errors (or maybe > there's the hardware compatibility mode that cannot know about LP_CAREFUL to > workaround some printer behaviour). In such case your patch is probably the > only way to go (but almost certainly for the software compatibility mode it > should be possible to report errors via parport_write as we do in 2.2.x). The tunelp man-page seems to think there are printers that need the LP_CAREFUL handling. I also noted that if I disconnect my printer from the computer, the data will no longer be lost. Apparently the printer confuses the parallel port when it is powered off. > > I also only get one DMA write timeout when putting the printer in > > offline mode during sending, instead of repeated timeouts as I got > > with the previous patch. > > I see, it makes sense to try to parport_write only when errors goes away, but I > think it's nicer to have lp_error or lp_check_status that loops internally in > interruptible mode if LP_ABORT isn't set via lptune. probably the code should > be restructured a bit. What do you think about the following patch? It also works for all the tests mentioned in my previous message. --- linux-2.4.0-prerelease/drivers/char/lp.c.orig Wed Jan 3 18:48:39 2001 +++ linux-2.4.0-prerelease/drivers/char/lp.c Thu Jan 4 00:45:52 2001 @@ -188,10 +188,7 @@ int error = 0; unsigned int last = lp_table[minor].last_error; unsigned char status = r_str(minor); - if ((status & LP_PERRORP) && !(LP_F(minor) & LP_CAREFUL)) - /* No error. */ - last = 0; - else if ((status & LP_POUTPA)) { + if ((status & LP_POUTPA)) { if (last != LP_POUTPA) { last = LP_POUTPA; printk(KERN_INFO "lp%d out of paper\n", minor); @@ -210,8 +207,7 @@ } error = -EIO; } else { - last = 0; /* Come here if LP_CAREFUL is set and no - errors are reported. */ + last = 0; /* Come here if no errors are reported. */ } lp_table[minor].last_error = last; @@ -222,6 +218,21 @@ return error; } +static int lp_wait_ready(int minor) +{ + int error = 0; + do { + error = lp_check_status (minor); + if (error && (LP_F(minor) & LP_ABORT)) + break; + if (signal_pending (current)) { + error = -EINTR; + break; + } + } while (error); + return error; +} + static ssize_t lp_write(struct file * file, const char * buf, size_t count, loff_t *ppos) { @@ -259,7 +270,7 @@ parport_set_timeout (lp_table[minor].dev, lp_table[minor].timeout); - if ((retv = lp_check_status (minor)) == 0) + if ((retv = lp_wait_ready (minor)) == 0) do { /* Write the data. */ written = parport_write (port, kbuf, copy_size); @@ -279,9 +290,9 @@ if (copy_size > 0) { /* incomplete write -> check error ! */ - int error = lp_check_status (minor); + int error = lp_wait_ready (minor); - if (LP_F(minor) & LP_ABORT) { + if (error) { if (retv == 0) retv = error; break; @@ -453,10 +464,7 @@ LP_F(minor) &= ~LP_ABORTOPEN; break; case LPCAREFUL: - if (arg) - LP_F(minor) |= LP_CAREFUL; - else - LP_F(minor) &= ~LP_CAREFUL; + /* Obsolete */ break; case LPWAIT: LP_WAIT(minor) = arg; --- linux-2.4.0-prerelease/drivers/parport/ieee1284.c.orig Wed Jan 3 18:50:02 2001 +++ linux-2.4.0-prerelease/drivers/parport/ieee1284.c Wed Jan 3 21:32:28 2001 @@ -524,7 +524,8 @@ PARPORT_STATUS_PAPEROUT, PARPORT_STATUS_PAPEROUT); if (r) - DPRINTK (KERN_INFO "%s: Timeout at event 31\n"); + DPRINTK (KERN_INFO "%s: Timeout at event 31\n", + port->name); port->ieee1284.phase = IEEE1284_PH_FWD_IDLE; DPRINTK (KERN_DEBUG "%s: ECP direction: forward\n", --- linux-2.4.0-prerelease/include/linux/lp.h.orig Thu Jan 4 00:21:15 2001 +++ linux-2.4.0-prerelease/include/linux/lp.h Thu Jan 4 00:21:21 2001 @@ -20,7 +20,6 @@ #define LP_NOPA 0x0010 #define LP_ERR 0x0020 #define LP_ABORT 0x0040 -#define LP_CAREFUL 0x0080 /* obsoleted -arca */ #define LP_ABORTOPEN 0x0100 #define LP_TRUST_IRQ_ 0x0200 /* obsolete */ -- Peter Österlund peter.osterlund@mailbox.swipnet.se Sköndalsvägen 35 http://home1.swipnet.se/~w-15919 S-128 66 Sköndal +46 8 942647 Sweden - 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/