-----Original Message----- From: Ville Syrjälä [mailto:ville.syrjala@linux.intel.com] Sent: Thursday, June 9, 2016 11:14 AM To: Kahola, Mika mika.kahola@intel.com Cc: dri-devel@lists.freedesktop.org; intel-gfx@lists.freedesktop.org; jim.bride@linux.intel.com; daniel.vetter@ffwll.ch Subject: Re: [PATCH v4 09/11] drm/i915: Check pixel rate for DP to VGA dongle
On Mon, Jun 06, 2016 at 04:29:11PM +0300, Mika Kahola wrote:
Filter out a mode that exceeds the max pixel rate setting for DP to VGA dongle. This is defined in DPCD register 0x81 if detailed cap info i.e. info field is 4 bytes long and it is available for DP downstream port.
The register defines the pixel rate divided by 8 in MP/s.
v2: DPCD read outs and computation moved to drm (Ville, Daniel) v3: Sink pixel rate computation moved to drm_dp_max_sink_dotclock() function (Daniel) v4: Use of drm_dp_helper.c routines to compute max pixel clock (Ville)
Signed-off-by: Mika Kahola mika.kahola@intel.com
drivers/gpu/drm/i915/intel_dp.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 096acbf0..1b94347 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -200,6 +200,23 @@ intel_dp_mode_valid(struct drm_connector
*connector,
int target_clock = mode->clock; int max_rate, mode_rate, max_lanes, max_link_clock; int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
- bool is_branch_device;
- int max_dp_clk;
- int type;
- uint8_t port_cap[4];
- is_branch_device = intel_dp-
dpcd[DP_DOWNSTREAMPORT_PRESENT] &
DP_DWN_STRM_PORT_PRESENT;- if (is_branch_device) {
drm_dp_downstream_port_cap(&intel_dp->aux, intel_dp-dpcd, +port_cap);
I'm pretty sure we already read out the downstream port caps in fact. Hmm, yeah ->downstream_ports. So no need for this, and I suppose no need for your helper for the readout either. Just always readoing out the full 16 bytes should be fine.
Right, I missed that one. We do read port caps with ->downstream_ports. I'll skip the helper routines regarding reading out port cap info.
type = drm_dp_downstream_type(intel_dp->dpcd,port_cap);
max_dp_clk = drm_dp_downstream_max_clock(intel_dp-dpcd, port_cap);
if ((type == DP_DS_PORT_TYPE_VGA) && (max_dp_clk > 0)){
Type check can be skipped if drm_dp_downstream_max_clock() just returns 0 for the "don't know" case.
max_dotclk = min(max_dotclk, max_dp_clk);}}
if (is_edp(intel_dp) && fixed_mode) { if (mode->hdisplay > fixed_mode->hdisplay)
-- 1.9.1
-- Ville Syrjälä Intel OTC