Re: [Intel-gfx] [PATCH 2/2] drm/i915: Get rid of intel_dp_dpcd_read_wake()

From: Ville Syrjälä
Date: Fri Mar 18 2016 - 12:41:52 EST

On Fri, Mar 18, 2016 at 06:12:35PM +0200, Ville Syrjälä wrote:
> On Fri, Mar 18, 2016 at 04:13:45PM +0200, Ville Syrjälä wrote:
> > On Thu, Mar 17, 2016 at 11:40:45AM -0400, Lyude wrote:
> > > Since we've fixed up drm_dp_dpcd_read() to allow for retries when things
> > > timeout, there's no use for having this function anymore. Good riddens.
> > >
> > > Signed-off-by: Lyude <cpaul@xxxxxxxxxx>
> > > ---
> > > drivers/gpu/drm/i915/intel_dp.c | 79 ++++++++++++-----------------------------
> > > 1 file changed, 22 insertions(+), 57 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> > > index cdc2c15..fb4cbbe5 100644
> > > --- a/drivers/gpu/drm/i915/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/intel_dp.c
> > > @@ -3190,47 +3190,14 @@ static void chv_dp_post_pll_disable(struct intel_encoder *encoder)
> > > }
> > >
> > > /*
> > > - * Native read with retry for link status and receiver capability reads for
> > > - * cases where the sink may still be asleep.
> > > - *
> > > - * Sinks are *supposed* to come up within 1ms from an off state, but we're also
> > > - * supposed to retry 3 times per the spec.
> > > - */
> > > -static ssize_t
> > > -intel_dp_dpcd_read_wake(struct drm_dp_aux *aux, unsigned int offset,
> > > - void *buffer, size_t size)
> > > -{
> > > - ssize_t ret;
> > > - int i;
> > > -
> > > - /*
> > > - * Sometime we just get the same incorrect byte repeated
> > > - * over the entire buffer. Doing just one throw away read
> > > - * initially seems to "solve" it.
> > > - */
> > > - drm_dp_dpcd_read(aux, DP_DPCD_REV, buffer, 1);
> >
> > NAK
> >
> > If people keep intentionally breaking my shit I'm going to become
> > really grumpy soon.
>
> Oh, and just in case someone wants to come up with a better kludge,
> I just spent a few minutes analyzing the behavior of this crappy
> monitor a.
>
> What happens is that when the monitor is fully powered up (LED is blue)
> things are fine. After the monitor goes to sleep (LED turns orange)
> the first DPCD read will produce garbage. Further DPCD reads are fine,
> even if I wait a significant amount of time between the reads, as long
> as the monitor didn't do a power on->off cycle in between. So it looks
> like it's always just the first read after power down that gets
> corrupted.
>
> Now I think I'll go and test how writes behave, assuming I can find a
> decently sized chunk of DPCD address space I can write. And maybe I
> should also try i2c-over-aux...

The first DPCD write after powerdown also got corrupted. But i2c-over-aux
seems unaffected for whatever reason.

>
> >
> > > -
> > > - for (i = 0; i < 3; i++) {
> > > - ret = drm_dp_dpcd_read(aux, offset, buffer, size);
> > > - if (ret == size)
> > > - return ret;
> > > - msleep(1);
> > > - }
> > > -
> > > - return ret;
> > > -}
> > > -
> > > -/*
> > > * Fetch AUX CH registers 0x202 - 0x207 which contain
> > > * link status information
> > > */
> > > bool
> > > intel_dp_get_link_status(struct intel_dp *intel_dp, uint8_t link_status[DP_LINK_STATUS_SIZE])
> > > {
> > > - return intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > - DP_LANE0_1_STATUS,
> > > - link_status,
> > > - DP_LINK_STATUS_SIZE) == DP_LINK_STATUS_SIZE;
> > > + return drm_dp_dpcd_read(&intel_dp->aux, DP_LANE0_1_STATUS, link_status,
> > > + DP_LINK_STATUS_SIZE) == DP_LINK_STATUS_SIZE;
> > > }
> > >
> > > /* These are source-specific values. */
> > > @@ -3865,8 +3832,8 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> > > struct drm_i915_private *dev_priv = dev->dev_private;
> > > uint8_t rev;
> > >
> > > - if (intel_dp_dpcd_read_wake(&intel_dp->aux, 0x000, intel_dp->dpcd,
> > > - sizeof(intel_dp->dpcd)) < 0)
> > > + if (drm_dp_dpcd_read(&intel_dp->aux, 0x000, intel_dp->dpcd,
> > > + sizeof(intel_dp->dpcd)) < 0)
> > > return false; /* aux transfer failed */
> > >
> > > DRM_DEBUG_KMS("DPCD: %*ph\n", (int) sizeof(intel_dp->dpcd), intel_dp->dpcd);
> > > @@ -3877,9 +3844,9 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> > > /* Check if the panel supports PSR */
> > > memset(intel_dp->psr_dpcd, 0, sizeof(intel_dp->psr_dpcd));
> > > if (is_edp(intel_dp)) {
> > > - intel_dp_dpcd_read_wake(&intel_dp->aux, DP_PSR_SUPPORT,
> > > - intel_dp->psr_dpcd,
> > > - sizeof(intel_dp->psr_dpcd));
> > > + drm_dp_dpcd_read(&intel_dp->aux, DP_PSR_SUPPORT,
> > > + intel_dp->psr_dpcd,
> > > + sizeof(intel_dp->psr_dpcd));
> > > if (intel_dp->psr_dpcd[0] & DP_PSR_IS_SUPPORTED) {
> > > dev_priv->psr.sink_support = true;
> > > DRM_DEBUG_KMS("Detected EDP PSR Panel.\n");
> > > @@ -3890,9 +3857,9 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> > > uint8_t frame_sync_cap;
> > >
> > > dev_priv->psr.sink_support = true;
> > > - intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > - DP_SINK_DEVICE_AUX_FRAME_SYNC_CAP,
> > > - &frame_sync_cap, 1);
> > > + drm_dp_dpcd_read(&intel_dp->aux,
> > > + DP_SINK_DEVICE_AUX_FRAME_SYNC_CAP,
> > > + &frame_sync_cap, 1);
> > > dev_priv->psr.aux_frame_sync = frame_sync_cap ? true : false;
> > > /* PSR2 needs frame sync as well */
> > > dev_priv->psr.psr2_support = dev_priv->psr.aux_frame_sync;
> > > @@ -3908,15 +3875,13 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> > > /* Intermediate frequency support */
> > > if (is_edp(intel_dp) &&
> > > (intel_dp->dpcd[DP_EDP_CONFIGURATION_CAP] & DP_DPCD_DISPLAY_CONTROL_CAPABLE) &&
> > > - (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_EDP_DPCD_REV, &rev, 1) == 1) &&
> > > + (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_DPCD_REV, &rev, 1) == 1) &&
> > > (rev >= 0x03)) { /* eDp v1.4 or higher */
> > > __le16 sink_rates[DP_MAX_SUPPORTED_RATES];
> > > int i;
> > >
> > > - intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > - DP_SUPPORTED_LINK_RATES,
> > > - sink_rates,
> > > - sizeof(sink_rates));
> > > + drm_dp_dpcd_read(&intel_dp->aux, DP_SUPPORTED_LINK_RATES,
> > > + sink_rates, sizeof(sink_rates));
> > >
> > > for (i = 0; i < ARRAY_SIZE(sink_rates); i++) {
> > > int val = le16_to_cpu(sink_rates[i]);
> > > @@ -3939,9 +3904,9 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> > > if (intel_dp->dpcd[DP_DPCD_REV] == 0x10)
> > > return true; /* no per-port downstream info */
> > >
> > > - if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_DOWNSTREAM_PORT_0,
> > > - intel_dp->downstream_ports,
> > > - DP_MAX_DOWNSTREAM_PORTS) < 0)
> > > + if (drm_dp_dpcd_read(&intel_dp->aux, DP_DOWNSTREAM_PORT_0,
> > > + intel_dp->downstream_ports,
> > > + DP_MAX_DOWNSTREAM_PORTS) < 0)
> > > return false; /* downstream port status fetch failed */
> > >
> > > return true;
> > > @@ -3955,11 +3920,11 @@ intel_dp_probe_oui(struct intel_dp *intel_dp)
> > > if (!(intel_dp->dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_OUI_SUPPORT))
> > > return;
> > >
> > > - if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_SINK_OUI, buf, 3) == 3)
> > > + if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_OUI, buf, 3) == 3)
> > > DRM_DEBUG_KMS("Sink OUI: %02hx%02hx%02hx\n",
> > > buf[0], buf[1], buf[2]);
> > >
> > > - if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_BRANCH_OUI, buf, 3) == 3)
> > > + if (drm_dp_dpcd_read(&intel_dp->aux, DP_BRANCH_OUI, buf, 3) == 3)
> > > DRM_DEBUG_KMS("Branch OUI: %02hx%02hx%02hx\n",
> > > buf[0], buf[1], buf[2]);
> > > }
> > > @@ -3975,7 +3940,7 @@ intel_dp_probe_mst(struct intel_dp *intel_dp)
> > > if (intel_dp->dpcd[DP_DPCD_REV] < 0x12)
> > > return false;
> > >
> > > - if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_MSTM_CAP, buf, 1)) {
> > > + if (drm_dp_dpcd_read(&intel_dp->aux, DP_MSTM_CAP, buf, 1)) {
> > > if (buf[0] & DP_MST_CAP) {
> > > DRM_DEBUG_KMS("Sink is MST capable\n");
> > > intel_dp->is_mst = true;
> > > @@ -4112,7 +4077,7 @@ stop:
> > > static bool
> > > intel_dp_get_sink_irq(struct intel_dp *intel_dp, u8 *sink_irq_vector)
> > > {
> > > - return intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > + return drm_dp_dpcd_read(&intel_dp->aux,
> > > DP_DEVICE_SERVICE_IRQ_VECTOR,
> > > sink_irq_vector, 1) == 1;
> > > }
> > > @@ -4122,7 +4087,7 @@ intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *sink_irq_vector)
> > > {
> > > int ret;
> > >
> > > - ret = intel_dp_dpcd_read_wake(&intel_dp->aux,
> > > + ret = drm_dp_dpcd_read(&intel_dp->aux,
> > > DP_SINK_COUNT_ESI,
> > > sink_irq_vector, 14);
> > > if (ret != 14)
> > > @@ -4383,7 +4348,7 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
> > > intel_dp->downstream_ports[0] & DP_DS_PORT_HPD) {
> > > uint8_t reg;
> > >
> > > - if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_SINK_COUNT,
> > > + if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT,
> > > &reg, 1) < 0)
> > > return connector_status_unknown;
> > >
> > > --
> > > 2.5.0
> > >
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> > --
> > Ville Syrjälä
> > Intel OTC
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
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--
Ville Syrjälä
Intel OTC