Date: Thu, 15 Feb 2018 19:53:21 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 225932] uplcom Prolific PL2302 doesn't support high baud rates Message-ID: <bug-225932-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=225932 Bug ID: 225932 Summary: uplcom Prolific PL2302 doesn't support high baud rates Product: Base System Version: 11.1-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: gabor.simon75@gmail.com Created attachment 190665 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=190665&action=edit proposed patch for high baudrate support 1., Current uplcom module supports only the pre-defined baud rates, because free baudrate setting requires a divisor calculating formula. The product page of the vendor refers to the Linux module source as a reference application (http://lxr.free-electrons.com/source/drivers/usb/serial/pl2303.c), in which the formula is implemented clearly. (The baseline frequency constant is about 1/1000 off from the one actually used by the binary drivers though.) After porting the formula, the baud rate can be set to any arbitrary value. 2., The current chip type detection is kind of black magic, while the ID values of the bcdDevice[0] are officially documented in the product datasheets (http://www.prolific.com.tw/US/ShowProduct.aspx?pcid=41&showlevel=0017-0037-0041) The current detection could not identify the type HXD chips, so disables the baud rates above 6 Mbaud, while the chip supports up to 12Mbaud. 3., The current interrupt callback doesn't process neither the overrun/parity/frame/break error flags, nor the RI and DSR status flags. As I needed the high bitrates, ported the baudrate formula from the Linux code , please decide if it is legal or not, there already was a "Determine the chip type. This algorithm is taken from Linux." comment in the code. I also checked the formula against the values used by the binary driver and corrected the baseline frequency. Also checked the so-called standard baudrates (that shall work by directly writing them to dwDTERate register) on a PL2303HX, and removed the non-working ones. (For those who want to play with the values: writing 0xf0-s with 8bit no parity produces one square wave per 10 bits (1 start, 8 data, 1 stop), so measuring the freqency on TxD gives 1/10th of the actual baud rate :D) I've attached the patch, the changed file (for an easier review) and the small freqency test I used. NOTE: I have only a PL2303HX (bcdDevice[0]==3) at hand now, so it would be great if someone with other models could test at least the detection code. -- You are receiving this mail because: You are the assignee for the bug.
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