Sorry for the top post... When the driver is done preparing a DMA, the drivers write using a writel or IGB_WRITE_REG to the TDT (transmit tail) register to indicate to the hardware there is more data to fetch. When the hardware processes all the data it moves the TDH (transmit head) register and interrupts (if the descriptors were set to do so) or writes the head write back (HWB) memory location.
Hope that helps. Also, you can download the 82575/82576 manual for the igb hardware from e1000.sf.net download area. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Roman Chertov Sent: Friday, July 25, 2008 12:20 PM To: e1000-devel@lists.sourceforge.net Subject: [E1000-devel] igb driver question Hello, I am looking at the igb driver and I have a question regarding packet transmission. I see that igb_xmit_frame_ring_adv is called by the stack to TX a packet. In that function, the packet gets mapped to some TX descriptor and eventually gets sent to the card via DMA. I am not clear as to which mechanism actually triggers the transmit. Does the card automatically do so when it gets a DMA transfer and then invokes an interrupt to clear the TX ring? Thanks in advance, Roman Chertov ------------------------------------------------------------------------ - This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel
