Date: Sat, 16 Aug 1997 17:52:23 -0700 (PDT) From: Vinay Bannai <vinay@agni.nuko.com> To: freebsd-hackers@freebsd.org Subject: Device drivers and DMA details?? Message-ID: <199708170052.RAA25354@agni.nuko.com>
next in thread | raw e-mail | index | archive | help
Hi folks, I had a few kernel and DMA related questions about a PCI driver I am about to finish. The DMA controller is built into the card. I have been able to successfully DMA back and forth several hundreds of bytes of data. My question being if the transfer size is greated than the physical page size, do we need to initiate separate DMA (or descriptors) for each page? Also, while examining the fxp driver, the fxp_start() seems to be invoked at the time of each incoming packet (or interrupt from the device). Wouldn't this not create a delay in sending packets? Or is it that the fxp_start() also gets invoked whenever a packet is shoved on the network IF queues? Thanks Vinay
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199708170052.RAA25354>