Re: [PATCH v11 2/3] tty: hvc: pass DMA capable memory to put_chars()

[Xianting Tian]

在 2021/10/26 下午1:10, Jiri Slaby 写道:
> On 15. 10. 21, 4:46, Xianting Tian wrote:
> > @@ -151,9 +142,11 @@ static uint32_t vtermnos[MAX_NR_HVC_CONSOLES] =
> >   static void hvc_console_print(struct console *co, const char *b,
> >                     unsigned count)
> >   {
> > -    char c[N_OUTBUF] __ALIGNED__;
> > +    char *c;
> >       unsigned i = 0, n = 0;
> >       int r, donecr = 0, index = co->index;
> > +    unsigned long flags;
> > +    struct hvc_struct *hp;
> >         /* Console access attempt outside of acceptable console 
> > range. */
> >       if (index >= MAX_NR_HVC_CONSOLES)
> > @@ -163,6 +156,13 @@ static void hvc_console_print(struct console 
> > *co, const char *b,
> >       if (vtermnos[index] == -1)
> >           return;
> >   +    hp = cons_hvcs[index];
> > +    if (!hp)
> > +        return;
>
> You effectively make the console unusable until someone calls 
> hvc_alloc() for this device, correct? This doesn't look right. Neither 
> you describe this change of behaviour in the commit log.

I mentioned such info in the commit log:
'Introduce another array(cons_hvcs[]) for hvc pointers next to the
cons_ops[] and vtermnos[] arrays. With the array, we can easily find
hvc's cons_outbuf and its lock.'

After you pointed it out, I just found what you said make sense, I checked the code hvc_console_print() can support print before hvc_alloc() is called when someone use hvc_instantiate() for an early console discovery method.
I send a patch to fix the issue?  or these serial pathches reverted fisrtly then I resend new version patches? thanks


> regards,