Le 05/11/2019 à 21:45, Hervé Poussineau a écrit : > Le 02/11/2019 à 18:15, Laurent Vivier a écrit : >> The card is not able to exit from exhaustion state, because >> while the drive consumes the buffers, the RRP is incremented >> (when the driver clears the ISR RBE bit), so it stays equal >> to RWP, and while RRP == RWP, the card thinks it is always >> in exhaustion state. So the driver consumes all the buffers, >> but the card cannot receive new ones. >> >> This patch fixes the problem by not incrementing RRP when >> the driver clears the ISR RBE bit. >> >> Signed-off-by: Laurent Vivier <laur...@vivier.eu> >> --- >> hw/net/dp8393x.c | 31 ++++++++++++++++--------------- >> 1 file changed, 16 insertions(+), 15 deletions(-) > > I checked the DP83932C specification, available at > https://www.eit.lth.se/fileadmin/eit/courses/datablad/Periphery/Communication/DP83932C.pdf > > > In the Buffer Resources Exhausted section (page 20): > "To continue reception after the last RBA is used, the system must supply > additional RRA descriptor(s), update the RWP register, and clear the RBE > bit in the ISR. The SONIC rereads the RRA after this bit is cleared." > > If I understand correctly, if the OS updates first the RWP and then > clear the RBE bit, > then RRP should be different of RWP in dp8393x_do_read_rra() ? Or did I > miss something?
No, I found that by debugging the problem, I didn't have the documentation. I'll rework this patch, relying on the doc to better understand the problem. Thanks, Laurent
