On 10/12/2011 04:36 PM, Markus Rechberger wrote:
We have 2 products which can perform better with increased Bulk transfers
Device No. 1: According to the hardware spec of on of our product Available Bulk Transfer Size are: - 188 * n bytes, where n = 1 ~ 256.
Although we can drive that one with 15K as well when setting the HW register down to it.
Device No. 2 only creates jitter video with Bulk transfer sizes which are below 24064 bytes, no such chipfeature is available to decrease the bulk transfer size. http://sundtek.de/images/dtvjitter2.jpg with transfer size of 24064: http://sundtek.de/images/gooddata.jpg
The patch takes the features of Device No. 1 into account allowing a maximum buffer of 48128 bytes.
Those issues have been evaluated with MacOSX and a customized patched Linux version. Device No. 2 also corrupts on MacOSX with too small packet sizes, Windows and Mac are using 24064 bytes.
You are constantly mixing the packet size and the transfer size.
Default Bulk Transfersize of device No. 1 is around 1-2k which leads to very high cpu usage, updating it to 15k lowers that one.
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