07.02.2019 21:02, Sowjanya Komatineni пишет: > >>>>>>> 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. >>> >> >> My understanding that I2C's max read/write sizes quirks are the payload >> limits, and so excluding the header size. Hence I'm not sure what you are >> trying to say, Thierry. >> >> Sowjanya, also.. it should be fine if you'll include the separate patch into >> this series, placing it before this DMA-patch. I just read your message as >> "patch separately from this series". > > OK, Will add that prior to DMA patch. V15 will include max transfer limit > update, dma resource releases on probe faiures, and other minor errors in V14 > feedback. > Will wait for any more feedbacks before releasing V15... >
Thanks, I'll add couple more minor comments then.
