From: Lyude Paul <lyude@redhat.com>
To: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
nouveau@lists.freedesktop.org
Cc: Rajeev Nandan <rajeevny@codeaurora.org>,
greg.depoire@gmail.com, open list <linux-kernel@vger.kernel.org>,
David Airlie <airlied@linux.ie>,
Sean Paul <seanpaul@chromium.org>,
Rodrigo Vivi <rodrigo.vivi@intel.com>
Subject: [PATCH v6 6/9] drm/i915/dpcd_bl: Return early in vesa_calc_max_backlight if we can't read PWMGEN_BIT_COUNT
Date: Fri, 14 May 2021 14:15:00 -0400 [thread overview]
Message-ID: <20210514181504.565252-7-lyude@redhat.com> (raw)
In-Reply-To: <20210514181504.565252-1-lyude@redhat.com>
If we can't read DP_EDP_PWMGEN_BIT_COUNT in
intel_dp_aux_vesa_calc_max_backlight() but do have a valid PWM frequency
defined in the VBT, we'll keep going in the function until we inevitably
fail on reading DP_EDP_PWMGEN_BIT_COUNT_CAP_MIN. There's not much point in
doing this, so just return early.
Signed-off-by: Lyude Paul <lyude@redhat.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
---
drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
index 781c7cd98d75..bf8e4ed56847 100644
--- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
@@ -449,11 +449,14 @@ static u32 intel_dp_aux_vesa_calc_max_backlight(struct intel_connector *connecto
int freq, fxp, fxp_min, fxp_max, fxp_actual, f = 1;
u8 pn, pn_min, pn_max;
- if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, &pn) == 1) {
- pn &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
- max_backlight = (1 << pn) - 1;
+ if (drm_dp_dpcd_readb(&intel_dp->aux, DP_EDP_PWMGEN_BIT_COUNT, &pn) != 1) {
+ drm_dbg_kms(&i915->drm, "Failed to read pwmgen bit count cap\n");
+ return 0;
}
+ pn &= DP_EDP_PWMGEN_BIT_COUNT_MASK;
+ max_backlight = (1 << pn) - 1;
+
/* Find desired value of (F x P)
* Note that, if F x P is out of supported range, the maximum value or
* minimum value will applied automatically. So no need to check that.
--
2.31.1
next prev parent reply other threads:[~2021-05-14 18:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-14 18:14 [PATCH v6 0/9] drm: Extract DPCD backlight helpers from i915, add support in nouveau Lyude Paul
2021-05-14 18:14 ` [PATCH v6 1/9] drm/i915/dpcd_bl: Remove redundant AUX backlight frequency calculations Lyude Paul
2021-05-21 20:03 ` Rodrigo Vivi
2021-06-01 19:13 ` Jani Nikula
2021-05-14 18:14 ` [PATCH v6 2/9] drm/i915/dpcd_bl: Handle drm_dpcd_read/write() return values correctly Lyude Paul
2021-05-14 18:14 ` [PATCH v6 3/9] drm/i915/dpcd_bl: Cleanup intel_dp_aux_vesa_enable_backlight() a bit Lyude Paul
2021-05-14 18:14 ` [PATCH v6 4/9] drm/i915/dpcd_bl: Cache some backlight capabilities in intel_panel.backlight Lyude Paul
2021-05-14 18:14 ` [PATCH v6 5/9] drm/i915/dpcd_bl: Move VESA backlight enabling code closer together Lyude Paul
2021-05-14 18:15 ` Lyude Paul [this message]
2021-05-14 18:15 ` [PATCH v6 7/9] drm/i915/dpcd_bl: Print return codes for VESA backlight failures Lyude Paul
2021-05-14 18:15 ` [PATCH v6 8/9] drm/dp: Extract i915's eDP backlight code into DRM helpers Lyude Paul
2021-05-21 20:02 ` Rodrigo Vivi
2021-05-14 18:15 ` [PATCH v6 9/9] drm/nouveau/kms/nv50-: Add basic DPCD backlight support for nouveau Lyude Paul
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