I'm reading Linux 2.6.21.5 ether.c very carefully trying to understand how it works (I want to integrate it with the PXA270 StrongARM XScale processor). I find many puzzling things about it.
In ether.c are the arrays fs_eth_function[] and hs_eth_function[] just there for testing purposes? Their presence continues to make no sense to me. See, for example, the lines which refer to fs_eth_function: http://lxr.linux.no/ident?i=fs_eth_function where it only ever gets set and never gets read. The initialization of mdlm_desc appears to have come in with the 2.6.21 kernel to support MDLM SAFE mode. The mdlm_desc struct only gets used to initialize poitners in the array fs_eth_function[] and hs_eth_function[] which both do not get used. So how was the addition of mdlm_desc necessary for MDLM SAFE support? Various descriptors get initialized into fs_eth_function[] and hs_eth_function[]. Only 3 of those descriptors (all of type usb_endpoint_descriptor) really get used and they get used by getting passed to usb_ep_autoconfig: fs_source_desc fs_sink_desc fs_status_desc So then does the Ethernet Gadget uses only 3 endpoints regardless of whether it is doing full CDC Ethernet, CDC Subset, CDC Subset/MDLM/SAFE, or RNDIS? That's the way it looks to me. Their high speed equivalents (the only other structs in ether.c of type usb_endpoint_descriptor) are effectively unused: hs_source_desc hs_sink_desc hs_status_desc Among the other effectively unused descriptor structs (they are only put in the unused fs_eth_function[] and hs_eth_function[] arrays): subset_data_intf header_desc mdlm_desc mdlm_detail_desc ether_desc Those mdlm_desc and mdlm_detail_desc fields were added for 2.6.21 to support MDLM/SAFE. But they are NOT used. Similarly, the fs_subset_descriptors() and hs_subset_descriptors() functions seem worthless because they set entries in the unused fs_eth_function[] and hs_eth_function[] arrays. Hey, I want to use this to do MDLM/SAFE with a Windows PC host. But for MDLM/SAFE is this ether.c a partial implementation or a working implementation that has pieces that aren't used? Randall Parker Vetronix Santa Barbara CA, USA 805-966-2000 x3141 ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
