[Intel-gfx] [PATCH] drm/i915/gvt: Fix bug in getting msg length in AUX CH registers handler

[Zhenyu Wang]

On 2023.07.31 19:20:33 +0800, Yan Zhao wrote:
> Msg length should be obtained from value written to AUX_CH_CTL register
> rather than from enum type of the register.
> 
> Commit 0cad796a2269  ("drm/i915: Use REG_BIT() & co. for AUX CH registers")
> incorrectly calculates the msg_length from reg type and yields below
> warning in intel_gvt_i2c_handle_aux_ch_write():
> "i915 0000:00:02.0: drm_WARN_ON(msg_length != 4)".
> 
> Fixes: 0cad796a2269 ("drm/i915: Use REG_BIT() & co. for AUX CH registers")
> Signed-off-by: Yan Zhao <yan.y.zhao at intel.com>
> ---

Thanks for the fix!

Reviewed-by: Zhenyu Wang <zhenyuw at linux.intel.com>

>  drivers/gpu/drm/i915/gvt/edid.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/gvt/edid.c b/drivers/gpu/drm/i915/gvt/edid.c
> index 2a0438f12a14..af9afdb53c7f 100644
> --- a/drivers/gpu/drm/i915/gvt/edid.c
> +++ b/drivers/gpu/drm/i915/gvt/edid.c
> @@ -491,7 +491,7 @@ void intel_gvt_i2c_handle_aux_ch_write(struct intel_vgpu *vgpu,
>  		return;
>  	}
>  
> -	msg_length = REG_FIELD_GET(DP_AUX_CH_CTL_MESSAGE_SIZE_MASK, reg);
> +	msg_length = REG_FIELD_GET(DP_AUX_CH_CTL_MESSAGE_SIZE_MASK, value);
>  
>  	// check the msg in DATA register.
>  	msg = vgpu_vreg(vgpu, offset + 4);
> -- 
> 2.17.1
> 
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