Re: [PATCH] accel/ivpu: Document why full JSM message size is always used

["Wachowski, Karol" <karol.wachowski@linux.intel.com>]

On 25-May-26 9:44, Dawid Osuchowski wrote:
> On 2026-05-22 11:32 AM, Karol Wachowski wrote:
>> Firmware expects IPC messages to always carry the full fixed
>> sizeof(struct vpu_jsm_msg) size. Sending the full struct also
>> ensures unused fields are zeroed, which maintains compatibility
>> when existing commands are extended with new fields in the future.
>>
>> Replace the misleading TODO comment with an explanation of the
>> actual intent.
>>
>> Signed-off-by: Karol Wachowski <karol.wachowski@linux.intel.com>
> 
> Reviewed-by: Dawid Osuchowski <dawid.osuchowski@linux.intel.com>

Thanks, applied to drm-misc-next.

> 
>> ---
>>   drivers/accel/ivpu/ivpu_ipc.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/accel/ivpu/ivpu_ipc.c b/drivers/accel/ivpu/ 
>> ivpu_ipc.c
>> index f47df092bb0d..9f1ba0c57442 100644
>> --- a/drivers/accel/ivpu/ivpu_ipc.c
>> +++ b/drivers/accel/ivpu/ivpu_ipc.c
>> @@ -97,7 +97,11 @@ ivpu_ipc_tx_prepare(struct ivpu_device *vdev, 
>> struct ivpu_ipc_consumer *cons,
>>       memset(tx_buf, 0, sizeof(*tx_buf));
>>       tx_buf->ipc.data_addr = jsm_vpu_addr;
>> -    /* TODO: Set data_size to actual JSM message size, not union of 
>> all messages */
>> +    /*
>> +     * Firmware expects full JSM message size regardless of the 
>> payload size.
>> +     * Unused fields must be zeroed to allow future extensions of 
>> existing
>> +     * commands without breaking compatibility.
>> +     */
>>       tx_buf->ipc.data_size = sizeof(*req);
>>       tx_buf->ipc.channel = cons->channel;
>>       tx_buf->ipc.src_node = 0;
>