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chip revisions. (A buggy taiwanese chip? I'm just shocked; shocked I tell you.) So far I have only observed the anomalous behavior on board with PCI revision 33 chips. At the moment, this seems to include only the Netgear FA310-TX rev D1 boards with chips labeled NGMC169B. (Possibly this means it's an 82c169B part from Lite-On.) The bug only manifests itself in promiscuous mode, and usually only at 10Mbps half-duplex. (I have not observed the problem in full-duplex mode, and I don't think it ever happens at 100Mbps.) The bug appears to be in the receiver DMA engine. Normally, the chip is programmed with a linked list of receiver descriptors, each with a receive buffer capable of holding a complete full-sized ethernet frame. During periods of heavy traffic (i.e. ping -c 100 -f 8100 <otherhost>), the receiver will sometimes appear to upload its entire FIFO memory contents instead of just uploading the desired received frame. The uploaded data will span several receive buffers, in spite of the fact that the chip has been told to only use one descriptor per frame, and appears to consist of previously transmitted frames with the correct received frame appended to the end. Unfortunately, there is no way to determine exactly how much data is uploaded when this happens; the chip doesn't tell you anything except the size of the desired received frame, and the amount of bogus data varies. Sometimes, the desired frame is also split across multiple buffers. The workaround is ugly and nasty. The driver assembles all of the data from the bogus frames into a single buffer. The receive buffers are always zeroed out, and we program the chip to always include the receive CRC at the end of each frame. We therefore know that we can start from the end of the buffer and scan back until we encounter a non-zero data byte, and say conclusively that this is the end of the desired frame. We can then subtract the frame length from this address to determine the real start of the frame, and copy it into an mbuf and pass it on. This is kludgy and time consuming, but it's better than dropping frames. It's not too bad since the problem only happens at 10Mbps. The workaround is only enabled for chips with PCI revision == 33. The LinkSys LNE100TX and Matrox FastNIC 10/100 cards use a revision 32 chip and work fine in promiscuous mode. Netgear support has confirmed that they "have some previous knowledge of problems in promiscuous mode" but didn't have a workaround. The people at Lite-On who would be able to suggest a possible fix are on vacation. So, I decided to implement a workaround of my own until I hear from them. I suppose this problem made it through Netgear's QA department since Windows doesn't normally use promiscuous mode, and if Windows doesn't need the feature than it can't possibly be important, right? Grrr. |
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.. | ||
adv_pci.c | ||
adw_pci.c | ||
ahc_pci.c | ||
brktree_reg.h | ||
brooktree848.c | ||
bt848_i2c.c | ||
bt848_i2c.h | ||
bt_pci.c | ||
cy_pci.c | ||
cy_pcireg.h | ||
dc21040reg.h | ||
dpt_pci.c | ||
dpt_pci.h | ||
es1370_reg.h | ||
es1370.c | ||
ide_pci.c | ||
ide_pcireg.h | ||
if_de.c | ||
if_devar.h | ||
if_ed_p.c | ||
if_en_pci.c | ||
if_fpa.c | ||
if_fxp.c | ||
if_fxpreg.h | ||
if_fxpvar.h | ||
if_lnc_p.c | ||
if_mx.c | ||
if_mxreg.h | ||
if_pn.c | ||
if_pnreg.h | ||
if_rl.c | ||
if_rlreg.h | ||
if_sr_p.c | ||
if_tl.c | ||
if_tlreg.h | ||
if_tx.c | ||
if_txvar.h | ||
if_vr.c | ||
if_vrreg.h | ||
if_vx_pci.c | ||
if_wb.c | ||
if_wbreg.h | ||
if_xl.c | ||
if_xlreg.h | ||
isp_pci.c | ||
locate.pl | ||
meteor_reg.h | ||
meteor.c | ||
ncr.c | ||
ncrreg.h | ||
pci_compat.c | ||
pci_ioctl.h | ||
pci.c | ||
pcic_p.c | ||
pcic_p.h | ||
pcireg.h | ||
pcisupport.c | ||
pcivar.h | ||
README.bt848 | ||
scsiiom.c | ||
simos.c | ||
simos.h | ||
wdc_p.c | ||
xrpu.c |
------------------------------------------------------------------------------- Recent versions of 3.0-current have the bktr driver built in. Older versions of 3.0 and all versions of 2.2 need to have the driver files installed by hand: cp ioctl_bt848.h /sys/i386/include/ cp brktree_reg.h brooktree848.c /sys/pci/ In /sys/conf/files add: pci/brooktree848.c optional bktr device-driver ------------------------------------------------------------------------------- In all cases you will need to add the driver to your kernel: In your kernel configuration file: controller pci0 #if you already have this line don't add it. device bktr0 There is no need to specify DMA channels nor interrupts for this driver. ------------------------------------------------------------------------------- Finally you need to create nodes for the driver: Create a video device: mknod /dev/bktr0 c 92 0 Create a tuner device: mknod /dev/tuner0 c 92 16 ------------------------------------------------------------------------------- The code attempts to auto-probe code to detect card/tuner types. The detected card is printed in the dmesg as the driver is loaded. If this fails to detect the proper card you can override it in brooktree848.c: #define OVERRIDE_CARD <card type> where <card type> is one of: CARD_UNKNOWN CARD_MIRO CARD_HAUPPAUGE CARD_STB CARD_INTEL ------------------------------------------------------------------------------- This model now separates the "tuner control" items into a minor device: minor device layout: xxxxxxxx xxxT UUUU UUUU: the card (ie UNIT) identifier, 0 thru 15 T == 0: video device T == 1: tuner device Access your tuner ioctl thru your tuner device handle and anything which controls the video capture process thru the video device handle. Certain ioctl()s such as video source are available thru both devices. ------------------------------------------------------------------------------- If your tuner does not work properly or is not recognized properly try setting the tuner type via or card type: sysctl -w hw.bt848.card=<integer> current valid values are 0 to 5 inclusive sysctl -w hw.bt848.tuner=<integer> where integer is a value from 1 to 10 systcl -w hw.bt848.reverse_mute=<1 | 0> to reverse the mute function in the driver set variable to 1. The exact format of the sysctl bt848 variable is: unit << 8 | value unit identifies the pci bt848 board to be affected 0 is the first bt848 board, 1 is the second bt848 board. value denotes the integer value for tuners is a value from 0 to 10 for reversing the mute function of the tuner the value is 1 or 0. to find out all the bt848 variables: sysctl hw.bt848 ------------------------------------------------------------------------------- The bt848 driver consists of: src/sys/i386/include/ioctl_bt848.h src/sys/pci/brktree_reg.h src/sys/pci/brooktree848.c