On 2015/5/27 12:13, Zhang, Yanmin wrote: > Resend as V1/V2 have email format issue. Sorry for bothering.
Greg, We have to abandon this patchset. Zhuang Jin Can, a USB expert, reviewed the patches. He says acm_tty_write already considers it carefully. acm_tty_write puts the urb to a delayed queue when acm->susp_count is not 0. acm_suspend adds 1 to acm->susp_count and acm_resume decreases 1 from it . Sorry for the bothering. Also thank Jin Can for the comments. Yanmin > > I use Thunderbird. It has no a button to enable LKML email simply. :) > > V3: Change email config to resend. > Add a space in comment. > > --- > > There is a scenario about cdc-acm utilization.Application opens > n_gsm tty and cdc-acm tty. cdc-acm tty connects to xhci device. > The application configures cdc-adm tty to n_gsm tty as ldisc tty. > > n_gsm=>cdc-acm=>xhci driver > > acm_tty_write can be called from n_gsm driver by ldisc connection, > and from application when application opens cdc-acm tty directly. > acm_tty_write wakes up the device by calling usb_autopm_get_interface_async, > which calls pm_runtime_get. However, pm_runtime_get can't wake up > the device before returning as it's an async wake up. Then, acm_tty_write > might access the device when it is off. > > The patchset fixes it by: > 1) add a new function usb_autopm_get_interface_upgrade to deal with > above 2 requirements; > 2) wake up device in n_gsm driver if n_gsm drivers calls cdc-acm driver; > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majord...@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
