From 9e124fe16ff24746d6de5a2ad685266d7bce0e08 Mon Sep 17 00:00:00 2001 From: Markus Armbruster Date: Mon, 26 May 2008 23:31:07 +0100 Subject: [PATCH] xen: Enable console tty by default in domU if it's not a dummy Without console= arguments on the kernel command line, the first console to register becomes enabled and the preferred console (the one behind /dev/console). This is normally tty (assuming CONFIG_VT_CONSOLE is enabled, which it commonly is). This is okay as long tty is a useful console. But unless we have the PV framebuffer, and it is enabled for this domain, tty0 in domU is merely a dummy. In that case, we want the preferred console to be the Xen console hvc0, and we want it without having to fiddle with the kernel command line. Commit b8c2d3dfbc117dff26058fbac316b8acfc2cb5f7 did that for us. Since we now have the PV framebuffer, we want to enable and prefer tty again, but only when PVFB is enabled. But even then we still want to enable the Xen console as well. Problem: when tty registers, we can't yet know whether the PVFB is enabled. By the time we can know (xenstore is up), the console setup game is over. Solution: enable console tty by default, but keep hvc as the preferred console. Change the preferred console to tty when PVFB probes successfully, unless we've been given console kernel parameters. Signed-off-by: Markus Armbruster Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Thomas Gleixner --- arch/x86/xen/enlighten.c | 4 +++- drivers/video/xen-fbfront.c | 25 +++++++++++++++++++++++++ include/linux/console.h | 2 ++ kernel/printk.c | 3 +++ 4 files changed, 33 insertions(+), 1 deletion(-) diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 1b4b5fa498b..6cfb708408e 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1256,8 +1256,10 @@ asmlinkage void __init xen_start_kernel(void) ? __pa(xen_start_info->mod_start) : 0; boot_params.hdr.ramdisk_size = xen_start_info->mod_len; - if (!is_initial_xendomain()) + if (!is_initial_xendomain()) { + add_preferred_console("tty", 0, NULL); add_preferred_console("hvc", 0, NULL); + } /* Start the world */ start_kernel(); diff --git a/drivers/video/xen-fbfront.c b/drivers/video/xen-fbfront.c index 619a6f8d65a..4e10876e62f 100644 --- a/drivers/video/xen-fbfront.c +++ b/drivers/video/xen-fbfront.c @@ -18,6 +18,7 @@ * frame buffer. */ +#include #include #include #include @@ -48,6 +49,7 @@ struct xenfb_info { static u32 xenfb_mem_len = XENFB_WIDTH * XENFB_HEIGHT * XENFB_DEPTH / 8; +static void xenfb_make_preferred_console(void); static int xenfb_remove(struct xenbus_device *); static void xenfb_init_shared_page(struct xenfb_info *); static int xenfb_connect_backend(struct xenbus_device *, struct xenfb_info *); @@ -348,6 +350,7 @@ static int __devinit xenfb_probe(struct xenbus_device *dev, if (ret < 0) goto error; + xenfb_make_preferred_console(); return 0; error_nomem: @@ -358,6 +361,28 @@ static int __devinit xenfb_probe(struct xenbus_device *dev, return ret; } +static __devinit void +xenfb_make_preferred_console(void) +{ + struct console *c; + + if (console_set_on_cmdline) + return; + + acquire_console_sem(); + for (c = console_drivers; c; c = c->next) { + if (!strcmp(c->name, "tty") && c->index == 0) + break; + } + release_console_sem(); + if (c) { + unregister_console(c); + c->flags |= CON_CONSDEV; + c->flags &= ~CON_PRINTBUFFER; /* don't print again */ + register_console(c); + } +} + static int xenfb_resume(struct xenbus_device *dev) { struct xenfb_info *info = dev->dev.driver_data; diff --git a/include/linux/console.h b/include/linux/console.h index a4f27fbdf54..248e6e3b9b7 100644 --- a/include/linux/console.h +++ b/include/linux/console.h @@ -108,6 +108,8 @@ struct console { struct console *next; }; +extern int console_set_on_cmdline; + extern int add_preferred_console(char *name, int idx, char *options); extern int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options); extern void register_console(struct console *); diff --git a/kernel/printk.c b/kernel/printk.c index 8fb01c32aa3..028ed75d486 100644 --- a/kernel/printk.c +++ b/kernel/printk.c @@ -121,6 +121,8 @@ struct console_cmdline static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; static int selected_console = -1; static int preferred_console = -1; +int console_set_on_cmdline; +EXPORT_SYMBOL(console_set_on_cmdline); /* Flag: console code may call schedule() */ static int console_may_schedule; @@ -890,6 +892,7 @@ static int __init console_setup(char *str) *s = 0; __add_preferred_console(buf, idx, options, brl_options); + console_set_on_cmdline = 1; return 1; } __setup("console=", console_setup);