On Fri, Jan 31, 2020 at 08:08:34AM +0000, Benjamin GAIGNARD wrote: > > On 1/31/20 12:22 AM, Dave Airlie wrote: > >>>> hi-actually yes, we should probably be using this instead of just dropping > >>>> this. Also, I didn't write this code originally I just refactored a bunch > >>>> of > >>>> it - Dave Airlied is the original author, but the original version of this > >>>> code was written ages ago. tbh, I think it's a safe bet to say that they > >>>> probably did mean to use this but forgot to and no one noticed until now. > >>> Hi, > >>> > >>> Any clue about how to use crc value ? Does it have to be checked > >>> against something else ? > >>> If crc are not matching what should we do of the data copied just before ? > >> We should be able to just take the CRC value from the sideband message and > >> then generate our own CRC value using the sideband message contents, and check > >> if the two are equal. If they aren't, something went wrong and we didn't > >> receive the message properly. > >> > >> Now as to what we should do when we have CRC mismatches? That's a bit more > >> difficult. If you have access to the DP MST spec, I suppose a place to start > >> figuring that out would be checking if there's a way for us to request that a > >> branch device resend whatever message it sent previously. If there isn't, I > >> guess we should just print an error in dmesg (possibly with a hexdump of the > >> failed message as well) and not forward the message to the driver. Not sure of > >> any better way of handling it then that > > Yeah I think this reflects what I wanted to do, I've no memory of a > > retransmit option in the spec, but I've away from it for a while. But > > we'd want to compare the CRC with what we got to make sure the are the > > same. > > Hmm, that far more complex than just fix compilation warnings :) > > I will split the patch in two: > > - one for of all other warnings, hopefully it can get reviewed > > - one for this crc4 variable. Does checking crc value and print an error > should be acceptable ? > > Something like: > > if (crc4 != msg->chunk[msg->curchunk_len - 1]) > > print_hex_dump(KERN_DEBUG, "wrong crc", DUMP_PREFIX_NONE, 16, 1, > msg->chunk, msg->curchunk_len, false); Yeah I think that should be reasonable as a start. Then we'll see how much the bug reports start flowing in ... -Daniel > > > Benjamin > > > > > > Dave. > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
