There it is, let me know what you think. This is what I wrote for 2.4.x
kernel, it should apply cleanly against the latest 2.4.27-pre1.
Jan
--- linux-2.4.27-pre1/drivers/usb/serial/ftdi_sio.h 2004-04-22 23:16:51.0
+0200
+++ linux-2.4.27-pre1-jc/drivers/usb/serial/ftdi_sio.h 2004-04-
On Tue, 20 Apr 2004 23:12:56 +0200 (CEST)
Jan Capek <[EMAIL PROTECTED]> wrote:
> currently I have a patch for 2.4
> kernel only. Is anyone interested in looking at the patch?
Just send it already.
-- Pete
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[EMAIL PROTECTED] wrote:
>
... snip snip ...
>
> Yup. At leat the Edgeport data suggests that the latency I am seeing
> isn't inherent to USB. I'm still wondering if it is somehow tunable
> though.
I have spoken to Ty about this seperately but to keep the information in
the list in case someo
On Fri, Mar 09, 2001 at 09:05:44AM -0500, [EMAIL PROTECTED] wrote:
> I once discovered that the standard UART drivers will only deliver data
> to user level processes on "kernel ticks". Since you are running a
> 100Hz scheduler, that would limit the native UARTS to 10ms minimum
> latency and it l
On 9 Mar, Greg KH wrote:
> I ran the program on two devices tonight, using a OHCI host controller
> I didn't patch the kernel to modify HZ like you mentioned, so I don't
> know if that makes a difference with the numbers or not:
>
> Inside Out Networks Edgeport/4
> port = /devfs/usb/tts/0
I ran the program on two devices tonight, using a OHCI host controller
I didn't patch the kernel to modify HZ like you mentioned, so I don't
know if that makes a difference with the numbers or not:
Inside Out Networks Edgeport/4
port = /devfs/usb/tts/0
baud = 38400
packet
On 8 Mar, Greg KH wrote:
> On Thu, Mar 08, 2001 at 10:47:30AM -0500, [EMAIL PROTECTED] wrote:
>> > Some USB to serial devices handle latencies better than others. But of
>> > course they cost more :)
>>
>> Naturally, ;-) ...I'm using stock Intel UHCI.
>
> No, I mean that the USB to serial dev
On Thu, Mar 08, 2001 at 10:47:30AM -0500, [EMAIL PROTECTED] wrote:
> > Some USB to serial devices handle latencies better than others. But of
> > course they cost more :)
>
> Naturally, ;-) ...I'm using stock Intel UHCI.
No, I mean that the USB to serial device _itself_ is probably where the
g
> I anticipated this and came up with about 5ms worst case:
>
> 1 Submit packet to USB drivers
> 2 data to UART
> 3 data through loopback
> 4 data from UART
> 5 data from USB drivers
At least for OHCI, an idle host controller "should" be able to handle
(1) and (2) in less than a frame on average
On 8 Mar, To: [EMAIL PROTECTED] wrote:
> On 8 Mar, Greg KH wrote:
>> On Wed, Mar 07, 2001 at 02:34:26PM -0500, [EMAIL PROTECTED] wrote:
>>> I found that a native UART has a latency of 1-2ms for a single byte.
>>> That latency increases with packet size. When run over the 8U232AM
>>> the 1 byte
On 8 Mar, Greg KH wrote:
> On Wed, Mar 07, 2001 at 02:34:26PM -0500, [EMAIL PROTECTED] wrote:
>> I found that a native UART has a latency of 1-2ms for a single byte.
>> That latency increases with packet size. When run over the 8U232AM
>> the 1 byte latency is about 16-17ms and remains about 15
On Wed, Mar 07, 2001 at 02:34:26PM -0500, [EMAIL PROTECTED] wrote:
> I found that a native UART has a latency of 1-2ms for a single byte.
> That latency increases with packet size. When run over the 8U232AM
> the 1 byte latency is about 16-17ms and remains about 15ms longer than
> the native UAR
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