Messages in this thread | | | Date | Wed, 21 Jan 2009 15:32:29 +0000 | From | Alan Cox <> | Subject | Re: tty_tiocmset() masks out TIOCM_RI and TIOCM_CD, which breaks rfcomm |
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> TIOCM_CD and TIOCM_RI to the list? Like this:
CD and RI are inputs which is why they are masked.
> Traditionally, RI (Ring Indicator) and CD (Carrier Detect) were > typically used for DCE -> DTE communication, so perhaps this is why > they were left off initially. However, when Bluetooth is used to
The cables end up doing the conversion so the PC world always sees them from the one end - even if they are in fact crossed over in the cable.
> It might be appropriate to include other signals as well, such as CTS > and DSR. However, these do not seem necessary for rfcomm, since the > rfcomm driver will interpret a DTR as a DSR and an RTS as a CTS. My > main concern is for RI and CD, for which there does not seem to be a > workaround.
I would have expected the driver to be remapping RI/CD just as it does for the DTR<->DSR RTS<->CTS cable switch around.
It's certainly possible to fix it, but that would need a double check on the existing drivers and that passing new suprise bits won't do any harm. The real question is what should the right behaviour be - and to me that seems to be to logically flip all the lines not just DTR/DSR RTS/CTS
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