Re: [Intel-gfx] [PATCH v2 2/5] drm/i915/guc: Add unaligned wc memcpy for copying GuC Log

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 06/12/2022 09:20, Alan Previn wrote:
> Add usage of unaligned wc mempy in read_update_log_buffer
> as newer formats of GuC debug-log-events are no longer
> guaranteed to be exactly 4-dwords long per event.

If this "newer format" applies to DG2 and GuC log has been "productized" 
there (as in we expect to tell users please collect and attach), pick a 
fixes tag so this gets into 6.2.

Regards,

Tvrtko

> Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
> Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> ---
>   drivers/gpu/drm/i915/gt/uc/intel_guc_log.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
> index c5a7aecd08ac..2fa952916120 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_log.c
> @@ -459,13 +459,16 @@ static void _guc_log_copy_debuglogs_for_relay(struct intel_guc_log *log)
>   
>   		/* Just copy the newly written data */
>   		if (read_offset > write_offset) {
> -			i915_memcpy_from_wc(dst_data, src_data, write_offset);
> +			if (!i915_memcpy_from_wc(dst_data, src_data, write_offset))
> +				i915_unaligned_memcpy_from_wc(dst_data, src_data, write_offset);
>   			bytes_to_copy = buffer_size - read_offset;
>   		} else {
>   			bytes_to_copy = write_offset - read_offset;
>   		}
> -		i915_memcpy_from_wc(dst_data + read_offset,
> -				    src_data + read_offset, bytes_to_copy);
> +		if (!i915_memcpy_from_wc(dst_data + read_offset,
> +					 src_data + read_offset, bytes_to_copy))
> +			i915_unaligned_memcpy_from_wc(dst_data + read_offset,
> +						      src_data + read_offset, bytes_to_copy);
>   
>   		src_data += buffer_size;
>   		dst_data += buffer_size;