On Tue, Jul 09, 2013 at 01:40:37PM +0300, Imre Deak wrote:
> DP 1.2 compatible displays may report a 5.4Gbps maximum bandwidth which
> the driver will treat as an invalid value and use 1.62Gbps instead. Fix
> this by capping to 2.7Gbps anything beyond the DP 1.1 bandwidth range.
Comments inline.
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 11eb697..c6dd61f 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -71,11 +71,16 @@ intel_dp_max_link_bw(struct intel_dp *intel_dp)
> {
> int max_link_bw = intel_dp->dpcd[DP_MAX_LINK_RATE];
>
> + if (max_link_bw > DP_LINK_BW_2_7)
> + return DP_LINK_BW_2_7;
> +
> switch (max_link_bw) {
I think putting it here is preferrable:
case DP_LINK_BW_5_4: /* 1.2 capable displays may advertise higher bw */
max_link_bw = DP_LINK_BW_2_7;
break;
Then we still get the WARN for unknown values greater than 0xa.
> case DP_LINK_BW_1_62:
> case DP_LINK_BW_2_7:
> break;
> default:
> + WARN(1, "invalid max DP link bw val %x, using 1.62Gbps\n",
> + max_link_bw);
> max_link_bw = DP_LINK_BW_1_62;
> break;
--
Chris Wilson, Intel Open Source Technology Centre
