From ca88479c1c3b7b1a9f94320745f5331e1de77f80 Mon Sep 17 00:00:00 2001 From: Keith Packard Date: Fri, 18 Nov 2011 11:09:24 -0800 Subject: [PATCH] drm/i915: Treat pre-gen4 backlight duty cycle value consistently For i945 and earlier chips, the backlight frequency value had the low bit (of 16) fixed to zero. The Pineview code path handled this by just exposing the backlight range as 15 bits while other chips had the backlight range limited to 0 .. 0xfffe. This patch makes everyone take the pineview code path, providing 15 bits of backlight duty cycle range which seems more than sufficient to me. Daniel Mack reported that writing 1 to bit 0 of the duty cycle register was causing problems on his Samsung X20 notebook, even when the duty cycle value was less than the maximum backlight value. (He tried a value of 29749 with max_brightness of 29750). This patch never writes a '1' to that bit. Signed-off-by: Keith Packard Reviewed-by: Takashi Iwai Reported-and-tested-by: Daniel Mack Cc: stable@kernel.org --- drivers/gpu/drm/i915/intel_panel.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index 21f60b7d69a3..04d79fd1dc9d 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -178,13 +178,10 @@ u32 intel_panel_get_max_backlight(struct drm_device *dev) if (HAS_PCH_SPLIT(dev)) { max >>= 16; } else { - if (IS_PINEVIEW(dev)) { + if (INTEL_INFO(dev)->gen < 4) max >>= 17; - } else { + else max >>= 16; - if (INTEL_INFO(dev)->gen < 4) - max &= ~1; - } if (is_backlight_combination_mode(dev)) max *= 0xff; @@ -203,13 +200,12 @@ u32 intel_panel_get_backlight(struct drm_device *dev) val = I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK; } else { val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK; - if (IS_PINEVIEW(dev)) + if (INTEL_INFO(dev)->gen < 4) val >>= 1; if (is_backlight_combination_mode(dev)) { u8 lbpc; - val &= ~1; pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc); val *= lbpc; } @@ -246,11 +242,9 @@ static void intel_panel_actually_set_backlight(struct drm_device *dev, u32 level } tmp = I915_READ(BLC_PWM_CTL); - if (IS_PINEVIEW(dev)) { - tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1); + if (INTEL_INFO(dev)->gen < 4) level <<= 1; - } else - tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK; + tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK; I915_WRITE(BLC_PWM_CTL, tmp | level); } -- 2.20.1