[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] Re: [PATCH v3 3/3] Use separate struct console structure for each hvc_console.
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; } Attachment:
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