[PATCH] Revert "drm/amd/display: Remove unused temp variable"

[Harry Wentland]

On 2022-02-22 21:28, Alex Deucher wrote:
> This reverts commit b1f0ab445ec609f9b58e0969c5d052b52d9a54e7.
> 
> This patch is not valid.  The driver needs to actually read the
> entries in the ring buffer.  Add a comment to make this clear.
> 
> Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/1916>> Cc: Maíra Canal <maira.canal at usp.br>
> Signed-off-by: Alex Deucher <alexander.deucher at amd.com>

Reviewed-by: Harry Wentland <harry.wentland at amd.com>

Harry

> ---
>  drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h b/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
> index d3088836d4e4..cb92ab4c8b98 100644
> --- a/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
> +++ b/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
> @@ -2918,8 +2918,15 @@ static inline void dmub_rb_flush_pending(const struct dmub_rb *rb)
>  	while (rptr != wptr) {
>  		uint64_t volatile *data = (uint64_t volatile *)((uint8_t *)(rb->base_address) + rptr);
>  		//uint64_t volatile *p = (uint64_t volatile *)data;
> +		uint64_t temp;
> +		uint8_t i;
>  
> -		*data += DMUB_RB_CMD_SIZE / sizeof(uint64_t);
> +		/* Don't remove this.
> +		 * The contents need to actually be read from the ring buffer
> +		 * for this function to be effective.
> +		 */
> +		for (i = 0; i < DMUB_RB_CMD_SIZE / sizeof(uint64_t); i++)
> +			temp = *data++;
>  
>  		rptr += DMUB_RB_CMD_SIZE;
>  		if (rptr >= rb->capacity)