On Thu, Mar 16, 2017 at 10:58:54PM +0200, Andy Shevchenko wrote:
> On Thu, Mar 16, 2017 at 4:55 PM, Robin Murphy <robin.murphy@xxxxxxx> wrote:
> > On 16/03/17 13:36, Russell King - ARM Linux wrote:
> >> On Thu, Mar 16, 2017 at 05:56:53PM +0530, Vignesh R wrote:
> >>> Using dev_name() as irq name during request_irq() might be misleading in
> >>> case of serial over PCI. Therefore use a better alternative name for
> >>> identifying serial port irqs as "serial" appended with serial_index of
> >>> the port. This ensures that "serial" string is always present in irq
> >>> name while port index will help in distinguishing b/w different ports.
> >>
> >> Wouldn't it be better to use the device name (iow, ttySx) rather than
> >> "serialx" ?
> >>
> >> Maybe a helper function in serial_core.c to format the device name into
> >> a supplied string, which can be re-used elsewhere, eg, uart_report_port()
> >> and uart_suspend_port(). IOW:
> >>
> >> const char *uart_port_name(char *buf, size_t n, struct uart_driver *drv,
> >> struct uart_port *port)
> >> {
> >> snprintf(buf, n, "%s%d", drv->dev_name,
> >> drv->tty_driver->name_base + port->line);
> >>
> >> return buf;
> >> }
> >>
> >> which means you can do this:
> >>
> >> char name[16];
> >>
> >> request_irq(..., uart_port_name(name, sizeof(name), driver, port), ...)
> >>
> >> which also avoids the allocation.
> >
> > ...and makes 'cat /proc/interrupts' particularly fun later:
> >
> > 8: 0 GICv2 72 Level � �h ����V!
> >
> > Unless a suitably long-lived string already exists somewhere else in the
> > serial core, the allocation is unavoidable, although kasprintf() (or its
> > devm_ variant) might make matters a little simpler.
>
> What prevents us to create a field in uart_port (uart8250_port?) where
> we put the uart_port_name() for future use as long as uart_port is
> alive?
Probably a good idea - I didn't check whether request_irq() just uses
the pointer to the string or takes a copy of the string (I should've
done before making the suggestion...)
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
--
To unsubscribe from this list: send the line "unsubscribe linux-serial" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
