On 28/09/2005 18:24, Paulo Marques wrote:
If my math is correct, these 2 entries are taking 46Mb + 30Mb -> 76Mb on
a computer that has only 112Mb available for the entire system. So
something is eating memory away like crazy.
Is there a known problem with this driver? Are there some patches that I
can try out?
It's a known problem. No patches yet, I'm afraid. What happens is that
the driver dynamically allocates URBs and transfer buffers for
everything written to it and submits them to the USB device's bulk
transfer queue where they sit until the UART has dealt with them.
Whenever the TTY layer asks the driver how much data it can write, the
answer from the driver is "lots", so there is no throttling of the
'write' path back to the application. The driver really needs to
modulate this answer according to how much data is queued up (and
possibly how quickly the queued data can be transmitted).
The "visor" driver used to have the same problem but got fixed in 2.6.10
by imposing an upper limit on the number of outstanding URBs. It seems
fairly simple-minded, but I guess it's preferable to running out of memory!
--
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