> > >> It became apparent to me that there is a problem here. The size of > > >> dma_buf is 4096 bytes and maximum message length is 4096 too, we have > > >> pushed 12 bytes packet_header to the buffer >and now there are 4084 > > >> bytes left for the message in the buffer. Hence transfer of 4KB will > > >> cause buffer overflow and either crash kernel or corrupt memory. One > > >> solution is to just always >push packet_header using PIO, other to > > >> reduce max_write_len or increase dma_buf size. > > > > > > Yes, This is known to me and I will add separate patch for this to > > > update quirks to take care for t186 and t194 to exclude packet hdr > > > lengths There was separate patch when quirks were added and it got merged > > > already from 5.0-rc1 but don’t want to sneak that here. Will send > > > separate patch to take care of this. > > > Need to update quirk to exclude packet header > > > > > > > No. This is a bug of this patch, it must be fixed in this patch as well. > > > > > I'm not sure we actually need this. My understanding is that it's really the > payload size that's 4 KiB and 64 KiB, respectively. I don't think that > includes the header. > > Thierry
As per the design, Yes that’s including the HEADER. Its total transfer per packet including header.
