Messages in this thread | | | From | Vincent Mailhol <> | Date | Sat, 5 Nov 2022 18:21:55 +0900 | Subject | Re: [virtio-dev] [RFC PATCH 1/1] can: virtio: Initial virtio CAN driver. |
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On Fry. 4 nov. 2022 at 20:13, Arnd Bergmann <arnd@kernel.org> wrote: > On Thu, Nov 3, 2022, at 13:26, Harald Mommer wrote: > > On 25.08.22 20:21, Arnd Bergmann wrote: > >> > ... > > The messages are not necessarily processed in sequence by the CAN stack. > > CAN is priority based. The lower the CAN ID the higher the priority. So > > a message with CAN ID 0x100 can surpass a message with ID 0x123 if the > > hardware is not just simple basic CAN controller using a single TX > > mailbox with a FIFO queue on top of it.
Really? I acknowledge that it is priority based *on the bus*, i.e. if two devices A and B on the same bus try to send CAN ID 0x100 and 0x123 at the same time, then device A will win the CAN arbitration. However, I am not aware of any devices which reorder their own stack according to the CAN IDs. If I first send CAN ID 0x123 and then ID 0x100 on the device stack, 0x123 would still go out first, right?
> > Thinking about this the code becomes more complex with the array. What I > > get from the device when the message has been processed is a pointer to > > the processed message by virtqueue_get_buf(). I can then simply do a > > list_del(), free the message and done. > > Ok
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