Russell King - ARM Linux wrote:
On Thu, Jan 21, 2010 at 11:06:53PM +0100, Wolfram Sang wrote:
CCing linux-serial
On Thu, Jan 21, 2010 at 10:26:03PM +0100, Valentin Longchamp wrote:
The imx CTS trigger level is left at its reset value that is 32
chars. Since the RX FIFO has 32 entries, when CTS is raised, the
FIFO already is full. However, some serial port devices first empty
their TX FIFO before stopping when CTS is raised, resulting in lost
chars.
? Isn't that a flaw of the other side? Have you spotted other serial drivers
doing the same as your patch?
Arguably, but it's common behaviour of 16550A's and similar.
First I wanted to fix the fact that the imx serial hardware only raises
the CTS pin when the oferflowing char begins to be set. I would have
solved this by setting the CTS trigger value to 31 instead of 32. But
when I talked with one colleague he told me about 16550A (that is
present nearly everywhere) that empty their TX FIFO, so I lowered it to 16.
Val
--
Valentin Longchamp, PhD Student, EPFL-STI-LSRO1
valentin.longchamp@xxxxxxx, Phone: +41216937827
http://people.epfl.ch/valentin.longchamp
MEB3494, Station 9, CH-1015 Lausanne
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