Bug 47921 - FTDI driver framing error with even parity
Summary: FTDI driver framing error with even parity
Status: RESOLVED INVALID
Alias: None
Product: Drivers
Classification: Unclassified
Component: USB (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: Greg Kroah-Hartman
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-09-24 21:33 UTC by Andrew
Modified: 2012-09-26 16:28 UTC (History)
0 users

See Also:
Kernel Version: 3.5.4
Subsystem:
Regression: No
Bisected commit-id:

Attachments
Timing diagram. No parity. Everything's fine. (15.38 KB, image/png)
2012-09-24 21:33 UTC, Andrew 		Details
Even parity. Occasional framing errors. (16.56 KB, image/png)
2012-09-24 21:34 UTC, Andrew 		Details
Add an attachment (proposed patch, testcase, etc.)

Description Andrew 2012-09-24 21:33:18 UTC 
Created attachment 80991 [details]
Timing diagram. No parity. Everything's fine. 

This is seen on widely used ftdi ft232rl chips. 
Setting the parity bit to something other then 'even' results in occasional framing errors in transmitting data.

Attached are the timing diagrams. 
First, when we use no parity bit, 
Second, when parity is even.
Comment 1 Andrew 2012-09-24 21:34:07 UTC 
Created attachment 81001 [details]
Even parity. Occasional framing errors.
Comment 2 Greg Kroah-Hartman 2012-09-24 22:04:37 UTC 
On Mon, Sep 24, 2012 at 09:33:18PM +0000, bugzilla-daemon@bugzilla.kernel.org wrote:
>            Summary: FTDI driver framing error with even parity

Please post this on the linux-usb@vger.kernel.org mailing list.
Comment 3 Andrew 2012-09-26 16:28:37 UTC 
Bug in the test code, not the ftdi driver. Closing as invalid.
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