Re: console issue since 3.6, console=ttyS1 hangs

[Sean Young <sean@mess.org>]

On Wed, Oct 26, 2016 at 01:16:16PM -0500, Nathan Zimmer wrote:
> On 10/25/2016 03:41 PM, Sean Young wrote:
> >On Mon, Oct 24, 2016 at 04:49:25PM -0500, Nathan Zimmer wrote:
> >>[    1.565062] serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
> >The isa probe driver find the serial port.
> >
> >>[    1.566453] serial 00:04: pnp_assign_resources, try dependent set 0
> >>[    1.567383] serial 00:04:   couldn't assign io 0 (min 0x2f8 max 0x2f8)
> >But then decides that the port is already in use (the existing serial driver).
> >>[    1.568366] serial 00:04: pnp_assign_resources failed (-16)
> >>[    1.569188] serial 00:04: unable to assign resources
> >>[    1.569924] serial: probe of 00:04 failed with error -16
> >Please try and boot 3.7.0 with "8250.share_irqs=1", maybe it will pick
> >irq 3 and it will be happy again, but that is just a guess.
> >
> >I think I have not fully understood what the failure is. Does the serial
> >port not work or does the boot hang? What are the symptoms?
> With console=ttyS1 the boot will "hang", sometimes it makes it all the way
> through but may take 30 minutes, instead of the 2-4 minutes this box

Where does it hang? Any error messages?

> >We might be able to fix the problem with a pnp quirk but 3.7 is has not had
> >any releases for a long time. We will need a reproduction on a concurrent
> >kernel so a patch can be written for that.
> Yes it still happens with 4.8+
> I had only started dwelling on 3.6/3.7 since that is where it first appears
> and don't have any attachment to those.

Ok. Please try to following patch. I'm not sure it is good enough to be
merged as-is, but should provide a start for testing. Output with
CONFIG_PNP_DEBUG_MESSAGES should show only irq 3 is available for the 
serial port now.

Sean

>From 3a1705a2e28f4385b778ad96d7c517b82ea860e2 Mon Sep 17 00:00:00 2001
From: Sean Young <sean@mess.org>
Date: Thu, 27 Oct 2016 20:13:50 +0100
Subject: [PATCH] PNP: Add quirk for BIOS advertising wrong irqs for serial
 port

Signed-off-by: Sean Young <sean@mess.org>
---
 drivers/pnp/quirks.c | 43 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/drivers/pnp/quirks.c b/drivers/pnp/quirks.c
index d28e3ab..8712161 100644
--- a/drivers/pnp/quirks.c
+++ b/drivers/pnp/quirks.c
@@ -66,6 +66,48 @@ static void quirk_awe32_resources(struct pnp_dev *dev)
 	}
 }
 
+static void quirk_serial_port(struct pnp_dev *dev)
+{
+	struct pnp_option *option;
+	struct pnp_irq *irq;
+	struct pnp_port *port;
+
+	list_for_each_entry(option, &dev->options, list) {
+		if (!pnp_option_is_dependent(option))
+			continue;
+
+		if (option->type == IORESOURCE_IO) {
+			port = &option->u.port;
+
+			if (port->min != 0x2f8 || port->max != 0x2f8 ||
+				port->size != 8 || port->align != 1)
+				return;
+		} else if (option->type == IORESOURCE_IRQ) {
+			pnp_irq_mask_t map;
+
+			irq = &option->u.irq;
+
+			bitmap_zero(map.bits, PNP_IRQ_NR);
+			__set_bit(3, map.bits);
+			__set_bit(4, map.bits);
+			__set_bit(5, map.bits);
+			__set_bit(6, map.bits);
+			__set_bit(7, map.bits);
+			__set_bit(10, map.bits);
+			__set_bit(11, map.bits);
+			__set_bit(12, map.bits);
+
+			if (!bitmap_equal(map.bits, irq->map.bits, PNP_IRQ_NR))
+				return;
+		}
+	}
+
+	if (irq && port) {
+		bitmap_zero(irq->map.bits, PNP_IRQ_NR);
+		__set_bit(3, irq->map.bits);
+	}
+}
+
 static void quirk_cmi8330_resources(struct pnp_dev *dev)
 {
 	struct pnp_option *option;
@@ -448,6 +490,7 @@ static struct pnp_fixup pnp_fixups[] = {
 #ifdef CONFIG_PCI
 	{"PNP0c02", quirk_intel_mch},
 #endif
+	{"PNP0c02", quirk_serial_port},
 	{""}
 };
 
-- 
2.7.4