On Thu, Feb 16, 2017 at 01:54:02PM +0000, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
>
> Use the "*batch++ = " style as in the ring emission for better
> readability and also simplify the logic a bit by consolidating
> the offset and size calculations and overflow checking. The
> latter is a programming error so it is not required to check
> for it after each write to the object, but rather do it once the
> whole state has been written and fail the driver if something
> went wrong.
>
> v2: Rebase.
>
> v3: Keep track of offsets and sizes in bytes for simplicity
> and rename function pointer variable to _fn suffix.
> (Chris Wilson)
>
> v4: Fix size calc broken in v3 and add alignment warning. (Chris Wilson)
>
> v5: Fix return code.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
> Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> (v2)
> Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> ---
> +static u32 *gen9_init_indirectctx_bb(struct intel_engine_cs *engine, u32 *batch)
> {
> /* Pad to end of cacheline */
> - while (index % CACHELINE_DWORDS)
> - wa_ctx_emit(batch, index, MI_NOOP);
> + while ((unsigned long)batch % CACHELINE_BYTES)
> + *batch++ = MI_NOOP;
>
> - return wa_ctx_end(wa_ctx, *offset = index, CACHELINE_DWORDS);
> + return batch;
> }
>
> -static int gen9_init_perctx_bb(struct intel_engine_cs *engine,
> - struct i915_wa_ctx_bb *wa_ctx,
> - uint32_t *batch,
> - uint32_t *offset)
> +static u32 *gen9_init_perctx_bb(struct intel_engine_cs *engine, u32 *batch)
> {
> - uint32_t index = wa_ctx_start(wa_ctx, *offset, CACHELINE_DWORDS);
> + *batch++ = MI_BATCH_BUFFER_END;
>
> - wa_ctx_emit(batch, index, MI_BATCH_BUFFER_END);
> -
> - return wa_ctx_end(wa_ctx, *offset = index, 1);
> + return batch;
> }
> + /*
> + * Emit the two workaround batch buffers, recording the offset from the
> + * start of the workaround batch buffer object for each and their
> + * respective sizes.
> + */
> + for (i = 0; i < ARRAY_SIZE(wa_bb_fn); i++) {
> + wa_bb[i]->offset = batch_ptr - batch;
> + if (WARN_ON(!IS_ALIGNED(wa_bb[i]->offset, CACHELINE_BYTES))) {
> + ret = -EINVAL;
> goto out;
> + }
Looks like a trap! If we add a third wa bb and forget to align the end
of the second.
Not a problem today, so
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
-Chris
--
Chris Wilson, Intel Open Source Technology Centre
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