Reviewed-by: Lyude Paul lyude@redhat.com Thanks!
On Wed, 2019-08-21 at 16:01 -0400, David Francis wrote:
With DSC, bpp can be a multiple of 1/16, so drm_dp_calc_pbn_mode is insufficient.
Add drm_dp_calc_pbn_mode_dsc, a function which is the same as drm_dp_calc_pbn_mode, but the bpp is in units of 1/16.
Cc: Lyude Paul lyude@redhat.com Cc: Nicholas Kazlauskas nicholas.kazlauskas@amd.com Signed-off-by: David Francis David.Francis@amd.com
drivers/gpu/drm/drm_dp_mst_topology.c | 43 +++++++++++++++++++++++++++ include/drm/drm_dp_mst_helper.h | 2 +- 2 files changed, 44 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c index 398e7314ea8b..34a5bdfc598b 100644 --- a/drivers/gpu/drm/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/drm_dp_mst_topology.c @@ -3588,6 +3588,49 @@ static int test_calc_pbn_mode(void) return 0; }
+/**
- drm_dp_calc_pbn_mode_dsc() - Calculate the PBN for a mode with DSC
enabled.
- @clock: dot clock for the mode
- @dsc_bpp: dsc bits per pixel x16 (e.g. dsc_bpp = 136 is 8.5 bpp)
- This uses the formula in the spec to calculate the PBN value for a mode,
- given that the mode is using DSC
- Returns:
- PBN required for this mode
- */
+int drm_dp_calc_pbn_mode_dsc(int clock, int dsc_bpp) +{
- u64 kbps;
- s64 peak_kbps;
- u32 numerator;
- u32 denominator;
- kbps = clock * dsc_bpp;
- /*
* margin 5300ppm + 300ppm ~ 0.6% as per spec, factor is 1.006* The unit of 54/64Mbytes/sec is an arbitrary unit chosen based on* common multiplier to render an integer PBN for all link rate/lane* counts combinations* calculate* peak_kbps *= (1/16) bppx16 to bpp* peak_kbps *= (1006/1000)* peak_kbps *= (64/54)* peak_kbps *= 8 convert to bytes** Divide numerator and denominator by 16 to avoid overflow*/- numerator = 64 * 1006 / 16;
- denominator = 54 * 8 * 1000 * 1000;
- kbps *= numerator;
- peak_kbps = drm_fixp_from_fraction(kbps, denominator);
- return drm_fixp2int_ceil(peak_kbps);
+} +EXPORT_SYMBOL(drm_dp_calc_pbn_mode_dsc);
/* we want to kick the TX after we've ack the up/down IRQs. */ static void drm_dp_mst_kick_tx(struct drm_dp_mst_topology_mgr *mgr) { diff --git a/include/drm/drm_dp_mst_helper.h b/include/drm/drm_dp_mst_helper.h index 2ba6253ea6d3..ddb518f2157a 100644 --- a/include/drm/drm_dp_mst_helper.h +++ b/include/drm/drm_dp_mst_helper.h @@ -611,7 +611,7 @@ struct edid *drm_dp_mst_get_edid(struct drm_connector *connector, struct drm_dp_
int drm_dp_calc_pbn_mode(int clock, int bpp);
+int drm_dp_calc_pbn_mode_dsc(int clock, int dsc_bpp);
bool drm_dp_mst_allocate_vcpi(struct drm_dp_mst_topology_mgr *mgr, struct drm_dp_mst_port *port, int pbn, int slots);