On Tue, Jun 26, 2012 at 04:34:21PM -0300, Mauro Carvalho Chehab wrote:
> New udev-182 seems to be buggy: even when usermode is enabled, it
> insists on needing that probe would defer any firmware requests.
> So, drivers with firmware need to defer probe for the first
> driver's core request, otherwise an useless penalty of 30 seconds
> happens, as udev will refuse to load any firmware.
>
> Signed-off-by: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
> ---
>
> Note: this patch adds an ugly printk there, in order to allow testing it better.
> This will be removed at the final version.
>
> drivers/media/video/em28xx/em28xx-cards.c | 39 +++++++++++++++++++++++++----
> 1 file changed, 34 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/media/video/em28xx/em28xx-cards.c b/drivers/media/video/em28xx/em28xx-cards.c
> index 9229cd2..9a1c16c 100644
> --- a/drivers/media/video/em28xx/em28xx-cards.c
> +++ b/drivers/media/video/em28xx/em28xx-cards.c
> @@ -60,6 +60,8 @@ static unsigned int card[] = {[0 ... (EM28XX_MAXBOARDS - 1)] = UNSET };
> module_param_array(card, int, NULL, 0444);
> MODULE_PARM_DESC(card, "card type");
>
> +static bool is_em28xx_initialized;
> +
> /* Bitmask marking allocated devices from 0 to EM28XX_MAXBOARDS - 1 */
> static unsigned long em28xx_devused;
>
> @@ -3167,11 +3169,14 @@ static int em28xx_usb_probe(struct usb_interface *interface,
> * postponed, as udev may not be ready yet to honour firmware
> * load requests.
> */
> +printk("em28xx: init = %d, userspace_is_disabled = %d, needs firmware = %d\n",
> + is_em28xx_initialized,
> + is_usermodehelp_disabled(), em28xx_boards[id->driver_info].needs_firmware);
debug code?
Also, this doesn't seem wise. probe() will be called and
is_em28xx_initialized will be 0 before it can be set if the device is
present when the module is loaded. But, if a new device is added to the
system after probe() already runs, is_em28xx_initialized will be 1, yet
it isn't true for this new device.
So this doesn't seem like a valid solution, even if you were wanting to
paper over a udev bug.
> if (em28xx_boards[id->driver_info].needs_firmware &&
> - is_usermodehelp_disabled()) {
> - printk_once(KERN_DEBUG DRIVER_NAME
> - ": probe deferred for board %d.\n",
> - (unsigned)id->driver_info);
> + (!is_em28xx_initialized || is_usermodehelp_disabled())) {
> + printk(KERN_DEBUG DRIVER_NAME
> + ": probe deferred for board %d.\n",
> + (unsigned)id->driver_info);
> return -EPROBE_DEFER;
> }
>
> @@ -3456,4 +3461,28 @@ static struct usb_driver em28xx_usb_driver = {
> .id_table = em28xx_id_table,
> };
>
> -module_usb_driver(em28xx_usb_driver);
Hint, if you are removing this macro, you can almost be assured that you
are doing something wrong :)
thanks,
greg k-h
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