On Tue, 2011-11-08 at 13:45 -0800, Miche Baker-Harvey wrote:
> It is possible to make any virtio_console port be a console
> by sending VIRITO_CONSOLE_CONSOLE_PORT. But hvc_alloc was
> using a single struct console hvc_console, which contains
> both an index and flags which are per-port.
>
> This adds a separate struct console for each virtio_console
> that is CONSOLE_PORT.
Hi Miche,
I'm testing this on powerpc and unfortunately it's working a little _too
well_. I end up with two struct consoles registered and so I get every
line of output twice :)
The problem is that we're registering two struct consoles. The first
obviously is hvc_console, either in hvc_console_init(), or in my case
from hvc_instantiate().
Then we register the allocated one in hvc_alloc(). But because they both
point back to the same hardware you get duplicate output.
We _do_ want to register a console early, in either/both
hvc_console_init() and hvc_instantiate(), because we want to have
console during boot prior to when hvc_alloc() gets called.
I think maybe we should be checking in hvc_alloc() whether we already
have hvc_console associated with the vtermno and if so we use
hvc_console instead of allocating a new one.
Patch below to do that, and works for me, but it's a bit of a hack,
there must be a better solution.
Finally I'm not sure how your patch affects the code in hvc_poll() which
checks hvc_console.index to do the SYSRQ hack.
cheers
diff --git a/drivers/tty/hvc/hvc_console.c b/drivers/tty/hvc/hvc_console.c
index fff35da..b249195 100644
--- a/drivers/tty/hvc/hvc_console.c
+++ b/drivers/tty/hvc/hvc_console.c
@@ -815,13 +815,15 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
kref_init(&hp->kref);
INIT_WORK(&hp->tty_resize, hvc_set_winsz);
- /*
- * Make each console its own struct console.
- */
- cp = kmemdup(&hvc_console, sizeof(*cp), GFP_KERNEL);
- if (!cp) {
- kfree(hp);
- return ERR_PTR(-ENOMEM);
+
+ if (hvc_console.index >= 0 && vtermnos[hvc_console.index] ==
hp->vtermno)
+ cp = &hvc_console;
+ else {
+ cp = kmemdup(&hvc_console, sizeof(*cp), GFP_KERNEL);
+ if (!cp) {
+ kfree(hp);
+ return ERR_PTR(-ENOMEM);
+ }
}
hp->hvc_console = cp;
@@ -850,7 +852,9 @@ struct hvc_struct *hvc_alloc(uint32_t vtermno, int data,
list_add_tail(&(hp->next), &hvc_structs);
spin_unlock(&hvc_structs_lock);
- register_console(cp);
+
+ if (cp != &hvc_console)
+ register_console(cp);
return hp;
}
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