Ben Dooks said the following: > On Thu, Dec 03, 2009 at 04:09:57PM +0100, Michael Lawnick wrote: >> Ben Dooks said the following: >> > On Tue, May 26, 2009 at 01:30:21PM +0200, Esben Haabendal wrote: >> >> On Tue, May 19, 2009 at 7:22 AM, Esben Haabendal <eha@xxxxxxxxxxxxxxxxxx> wrote: >> >> > This fixes MAL (arbitration lost) bug caused by illegal use of >> >> > RSTA (repeated START) after STOP condition generated after last byte >> >> > of reads. With this patch, it is possible to do an i2c_transfer() with >> >> > additional i2c_msg's following the I2C_M_RD messages. >> >> > >> >> > It still needs to be resolved if it is possible to fix this issue >> >> > by removing the STOP condition after reads in a robust way. >> >> > >> >> > Signed-off-by: Esben Haabendal <eha@xxxxxxxxxxxxxxxxxx> >> >> > --- >> >> > ?drivers/i2c/busses/i2c-mpc.c | ? ?9 +++++++-- >> >> > ?1 files changed, 7 insertions(+), 2 deletions(-) >> >> >> >> Any blockers to get this accepted? >> > >> > It would be nice to get an ack from someone who can actually test >> > the driver before getting this merged. >> > >> What is the state of this patch? >> Shouldn't we attack the problem on a more general way by inventing a >> Flag I2C_M_RESTART (or better I2C_M_NO_RESTART for backward compatibility)? >> This way the client driver is able to decide what it needs. If we do the >> choice within adapter, chance is about 50% to be wrong. > > The documentation for 'struct i2c_msg' already says the STOP should only > be generated for the last message of the transfer. If STOP is being > generated for a message that isn't the last in the transfer than this > is incorrect behaviour. Ah, now I see, this is a mpc-only problem of implementation (automatically generating stop in read function). I couldn't find the above mentioned specification of STOP/RESTART (seems I need new glasses) and was worried about whether my own implementation for OCTEON is correct. Thank you. -- Michael -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
