Re: [PATCH 06/48] drm/radeon/kms: add initial DCE6 display watermark support

[Jerome Glisse <j.glisse@gmail.com>]

On Tue, 2012-03-20 at 17:18 -0400, alexdeucher@gmail.com wrote:
> From: Alex Deucher <alexander.deucher@amd.com>
> 
> Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
> ---
>  drivers/gpu/drm/radeon/Makefile      |    2 +-
>  drivers/gpu/drm/radeon/radeon_asic.h |    3 +
>  drivers/gpu/drm/radeon/si.c          |  486 ++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/radeon/sid.h         |   46 ++++
>  4 files changed, 536 insertions(+), 1 deletions(-)
>  create mode 100644 drivers/gpu/drm/radeon/si.c
>  create mode 100644 drivers/gpu/drm/radeon/sid.h
> 
> diff --git a/drivers/gpu/drm/radeon/Makefile b/drivers/gpu/drm/radeon/Makefile
> index 8410415..fa3e704 100644
> --- a/drivers/gpu/drm/radeon/Makefile
> +++ b/drivers/gpu/drm/radeon/Makefile
> @@ -71,7 +71,7 @@ radeon-y += radeon_device.o radeon_asic.o radeon_kms.o \
>  	r600_blit_kms.o radeon_pm.o atombios_dp.o r600_audio.o r600_hdmi.o \
>  	evergreen.o evergreen_cs.o evergreen_blit_shaders.o evergreen_blit_kms.o \
>  	radeon_trace_points.o ni.o cayman_blit_shaders.o atombios_encoders.o \
> -	radeon_semaphore.o radeon_sa.o atombios_i2c.o
> +	radeon_semaphore.o radeon_sa.o atombios_i2c.o si.o
>  
>  radeon-$(CONFIG_COMPAT) += radeon_ioc32.o
>  radeon-$(CONFIG_VGA_SWITCHEROO) += radeon_atpx_handler.o
> diff --git a/drivers/gpu/drm/radeon/radeon_asic.h b/drivers/gpu/drm/radeon/radeon_asic.h
> index b8f0a16..007f0f6 100644
> --- a/drivers/gpu/drm/radeon/radeon_asic.h
> +++ b/drivers/gpu/drm/radeon/radeon_asic.h
> @@ -461,4 +461,7 @@ void cayman_vm_set_page(struct radeon_device *rdev, struct radeon_vm *vm,
>  			unsigned pfn, uint64_t addr, uint32_t flags);
>  int evergreen_ib_parse(struct radeon_device *rdev, struct radeon_ib *ib);
>  
> +/* DCE6 - SI */
> +void dce6_bandwidth_update(struct radeon_device *rdev);
> +
>  #endif
> diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
> new file mode 100644
> index 0000000..39c64df
> --- /dev/null
> +++ b/drivers/gpu/drm/radeon/si.c
> @@ -0,0 +1,486 @@
> +/*
> + * Copyright 2011 Advanced Micro Devices, Inc.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + *
> + * Authors: Alex Deucher
> + */
> +#include "drmP.h"
> +#include "radeon.h"
> +#include "radeon_asic.h"
> +#include "radeon_drm.h"
> +#include "sid.h"
> +#include "atom.h"
> +
> +/* watermark setup */
> +static u32 dce6_line_buffer_adjust(struct radeon_device *rdev,
> +				   struct radeon_crtc *radeon_crtc,
> +				   struct drm_display_mode *mode,
> +				   struct drm_display_mode *other_mode)
> +{
> +	u32 tmp;
> +	/*
> +	 * Line Buffer Setup
> +	 * There are 3 line buffers, each one shared by 2 display controllers.
> +	 * DC_LB_MEMORY_SPLIT controls how that line buffer is shared between
> +	 * the display controllers.  The paritioning is done via one of four
> +	 * preset allocations specified in bits 21:20:
> +	 *  0 - half lb
> +	 *  2 - whole lb, other crtc must be disabled
> +	 */
> +	/* this can get tricky if we have two large displays on a paired group
> +	 * of crtcs.  Ideally for multiple large displays we'd assign them to
> +	 * non-linked crtcs for maximum line buffer allocation.
> +	 */
> +	if (radeon_crtc->base.enabled && mode) {
> +		if (other_mode)
> +			tmp = 0; /* 1/2 */
> +		else
> +			tmp = 2; /* whole */
> +	} else
> +		tmp = 0;
> +
> +	WREG32(DC_LB_MEMORY_SPLIT + radeon_crtc->crtc_offset,
> +	       DC_LB_MEMORY_CONFIG(tmp));
> +
> +	if (radeon_crtc->base.enabled && mode) {
> +		switch (tmp) {
> +		case 0:
> +		default:
> +			return 4096 * 2;
> +		case 2:
> +			return 8192 * 2;
> +		}
> +	}
> +
> +	/* controller not enabled, so no lb used */
> +	return 0;
> +}
> +
> +static u32 dce6_get_number_of_dram_channels(struct radeon_device *rdev)
> +{
> +	u32 tmp = RREG32(MC_SHARED_CHMAP);
> +
> +	switch ((tmp & NOOFCHAN_MASK) >> NOOFCHAN_SHIFT) {
> +	case 0:
> +	default:
> +		return 1;
> +	case 1:
> +		return 2;
> +	case 2:
> +		return 4;
> +	case 3:
> +		return 8;
> +	case 4:
> +		return 3;
> +	case 5:
> +		return 6;
> +	case 6:
> +		return 10;
> +	case 7:
> +		return 12;
> +	case 8:
> +		return 16;
> +	}
> +}
> +
> +struct dce6_wm_params {
> +	u32 dram_channels; /* number of dram channels */
> +	u32 yclk;          /* bandwidth per dram data pin in kHz */
> +	u32 sclk;          /* engine clock in kHz */
> +	u32 disp_clk;      /* display clock in kHz */
> +	u32 src_width;     /* viewport width */
> +	u32 active_time;   /* active display time in ns */
> +	u32 blank_time;    /* blank time in ns */
> +	bool interlaced;    /* mode is interlaced */
> +	fixed20_12 vsc;    /* vertical scale ratio */
> +	u32 num_heads;     /* number of active crtcs */
> +	u32 bytes_per_pixel; /* bytes per pixel display + overlay */
> +	u32 lb_size;       /* line buffer allocated to pipe */
> +	u32 vtaps;         /* vertical scaler taps */
> +};
> +
> +static u32 dce6_dram_bandwidth(struct dce6_wm_params *wm)
> +{
> +	/* Calculate raw DRAM Bandwidth */
> +	fixed20_12 dram_efficiency; /* 0.7 */
> +	fixed20_12 yclk, dram_channels, bandwidth;
> +	fixed20_12 a;
> +
> +	a.full = dfixed_const(1000);
> +	yclk.full = dfixed_const(wm->yclk);
> +	yclk.full = dfixed_div(yclk, a);
> +	dram_channels.full = dfixed_const(wm->dram_channels * 4);
> +	a.full = dfixed_const(10);
> +	dram_efficiency.full = dfixed_const(7);
> +	dram_efficiency.full = dfixed_div(dram_efficiency, a);
> +	bandwidth.full = dfixed_mul(dram_channels, yclk);
> +	bandwidth.full = dfixed_mul(bandwidth, dram_efficiency);
> +
> +	return dfixed_trunc(bandwidth);
> +}
> +
> +static u32 dce6_dram_bandwidth_for_display(struct dce6_wm_params *wm)
> +{
> +	/* Calculate DRAM Bandwidth and the part allocated to display. */
> +	fixed20_12 disp_dram_allocation; /* 0.3 to 0.7 */
> +	fixed20_12 yclk, dram_channels, bandwidth;
> +	fixed20_12 a;
> +
> +	a.full = dfixed_const(1000);
> +	yclk.full = dfixed_const(wm->yclk);
> +	yclk.full = dfixed_div(yclk, a);
> +	dram_channels.full = dfixed_const(wm->dram_channels * 4);
> +	a.full = dfixed_const(10);
> +	disp_dram_allocation.full = dfixed_const(3); /* XXX worse case value 0.3 */
> +	disp_dram_allocation.full = dfixed_div(disp_dram_allocation, a);
> +	bandwidth.full = dfixed_mul(dram_channels, yclk);
> +	bandwidth.full = dfixed_mul(bandwidth, disp_dram_allocation);
> +
> +	return dfixed_trunc(bandwidth);
> +}
> +
> +static u32 dce6_data_return_bandwidth(struct dce6_wm_params *wm)
> +{
> +	/* Calculate the display Data return Bandwidth */
> +	fixed20_12 return_efficiency; /* 0.8 */
> +	fixed20_12 sclk, bandwidth;
> +	fixed20_12 a;
> +
> +	a.full = dfixed_const(1000);
> +	sclk.full = dfixed_const(wm->sclk);
> +	sclk.full = dfixed_div(sclk, a);
> +	a.full = dfixed_const(10);
> +	return_efficiency.full = dfixed_const(8);
> +	return_efficiency.full = dfixed_div(return_efficiency, a);
> +	a.full = dfixed_const(32);
> +	bandwidth.full = dfixed_mul(a, sclk);
> +	bandwidth.full = dfixed_mul(bandwidth, return_efficiency);
> +
> +	return dfixed_trunc(bandwidth);
> +}
> +
> +static u32 dce6_get_dmif_bytes_per_request(struct dce6_wm_params *wm)
> +{
> +	return 32;
> +}

Why not just define a constant instead of having a function ?

> +
> +static u32 dce6_dmif_request_bandwidth(struct dce6_wm_params *wm)
> +{
> +	/* Calculate the DMIF Request Bandwidth */
> +	fixed20_12 disp_clk_request_efficiency; /* 0.8 */
> +	fixed20_12 disp_clk, sclk, bandwidth;
> +	fixed20_12 a, b1, b2;
> +	u32 min_bandwidth;
> +
> +	a.full = dfixed_const(1000);
> +	disp_clk.full = dfixed_const(wm->disp_clk);
> +	disp_clk.full = dfixed_div(disp_clk, a);
> +	a.full = dfixed_const(dce6_get_dmif_bytes_per_request(wm) / 2);
> +	b1.full = dfixed_mul(a, disp_clk);
> +
> +	a.full = dfixed_const(1000);
> +	sclk.full = dfixed_const(wm->sclk);
> +	sclk.full = dfixed_div(sclk, a);
> +	a.full = dfixed_const(dce6_get_dmif_bytes_per_request(wm));
> +	b2.full = dfixed_mul(a, sclk);
> +
> +	a.full = dfixed_const(10);
> +	disp_clk_request_efficiency.full = dfixed_const(8);
> +	disp_clk_request_efficiency.full = dfixed_div(disp_clk_request_efficiency, a);
> +
> +	min_bandwidth = min(dfixed_trunc(b1), dfixed_trunc(b2));
> +
> +	a.full = dfixed_const(min_bandwidth);
> +	bandwidth.full = dfixed_mul(a, disp_clk_request_efficiency);
> +
> +	return dfixed_trunc(bandwidth);
> +}
> +
> +static u32 dce6_available_bandwidth(struct dce6_wm_params *wm)
> +{
> +	/* Calculate the Available bandwidth. Display can use this temporarily but not in average. */
> +	u32 dram_bandwidth = dce6_dram_bandwidth(wm);
> +	u32 data_return_bandwidth = dce6_data_return_bandwidth(wm);
> +	u32 dmif_req_bandwidth = dce6_dmif_request_bandwidth(wm);
> +
> +	return min(dram_bandwidth, min(data_return_bandwidth, dmif_req_bandwidth));
> +}
> +
> +static u32 dce6_average_bandwidth(struct dce6_wm_params *wm)
> +{
> +	/* Calculate the display mode Average Bandwidth
> +	 * DisplayMode should contain the source and destination dimensions,
> +	 * timing, etc.
> +	 */
> +	fixed20_12 bpp;
> +	fixed20_12 line_time;
> +	fixed20_12 src_width;
> +	fixed20_12 bandwidth;
> +	fixed20_12 a;
> +
> +	a.full = dfixed_const(1000);
> +	line_time.full = dfixed_const(wm->active_time + wm->blank_time);
> +	line_time.full = dfixed_div(line_time, a);
> +	bpp.full = dfixed_const(wm->bytes_per_pixel);
> +	src_width.full = dfixed_const(wm->src_width);
> +	bandwidth.full = dfixed_mul(src_width, bpp);
> +	bandwidth.full = dfixed_mul(bandwidth, wm->vsc);
> +	bandwidth.full = dfixed_div(bandwidth, line_time);
> +
> +	return dfixed_trunc(bandwidth);
> +}
> +
> +static u32 dce6_latency_watermark(struct dce6_wm_params *wm)
> +{
> +	/* First calcualte the latency in ns */
> +	u32 mc_latency = 2000; /* 2000 ns. */
> +	u32 available_bandwidth = dce6_available_bandwidth(wm);
> +	u32 worst_chunk_return_time = (512 * 8 * 1000) / available_bandwidth;
> +	u32 cursor_line_pair_return_time = (128 * 4 * 1000) / available_bandwidth;
> +	u32 dc_latency = 40000000 / wm->disp_clk; /* dc pipe latency */
> +	u32 other_heads_data_return_time = ((wm->num_heads + 1) * worst_chunk_return_time) +
> +		(wm->num_heads * cursor_line_pair_return_time);
> +	u32 latency = mc_latency + other_heads_data_return_time + dc_latency;
> +	u32 max_src_lines_per_dst_line, lb_fill_bw, line_fill_time;
> +	u32 tmp, dmif_size = 12288;
> +	fixed20_12 a, b, c;
> +
> +	if (wm->num_heads == 0)
> +		return 0;
> +
> +	a.full = dfixed_const(2);
> +	b.full = dfixed_const(1);
> +	if ((wm->vsc.full > a.full) ||
> +	    ((wm->vsc.full > b.full) && (wm->vtaps >= 3)) ||
> +	    (wm->vtaps >= 5) ||
> +	    ((wm->vsc.full >= a.full) && wm->interlaced))
> +		max_src_lines_per_dst_line = 4;
> +	else
> +		max_src_lines_per_dst_line = 2;
> +
> +	a.full = dfixed_const(available_bandwidth);
> +	b.full = dfixed_const(wm->num_heads);
> +	a.full = dfixed_div(a, b);
> +
> +	b.full = dfixed_const(mc_latency + 512);
> +	c.full = dfixed_const(wm->disp_clk);
> +	b.full = dfixed_div(b, c);
> +
> +	c.full = dfixed_const(dmif_size);
> +	b.full = dfixed_div(c, b);
> +
> +	tmp = min(dfixed_trunc(a), dfixed_trunc(b));
> +
> +	b.full = dfixed_const(1000);
> +	c.full = dfixed_const(wm->disp_clk);
> +	b.full = dfixed_div(c, b);
> +	c.full = dfixed_const(wm->bytes_per_pixel);
> +	b.full = dfixed_mul(b, c);
> +
> +	lb_fill_bw = min(tmp, dfixed_trunc(b));
> +
> +	a.full = dfixed_const(max_src_lines_per_dst_line * wm->src_width * wm->bytes_per_pixel);
> +	b.full = dfixed_const(1000);
> +	c.full = dfixed_const(lb_fill_bw);
> +	b.full = dfixed_div(c, b);
> +	a.full = dfixed_div(a, b);
> +	line_fill_time = dfixed_trunc(a);
> +
> +	if (line_fill_time < wm->active_time)
> +		return latency;
> +	else
> +		return latency + (line_fill_time - wm->active_time);
> +
> +}
> +
> +static bool dce6_average_bandwidth_vs_dram_bandwidth_for_display(struct dce6_wm_params *wm)
> +{
> +	if (dce6_average_bandwidth(wm) <=
> +	    (dce6_dram_bandwidth_for_display(wm) / wm->num_heads))
> +		return true;
> +	else
> +		return false;
> +};
> +
> +static bool dce6_average_bandwidth_vs_available_bandwidth(struct dce6_wm_params *wm)
> +{
> +	if (dce6_average_bandwidth(wm) <=
> +	    (dce6_available_bandwidth(wm) / wm->num_heads))
> +		return true;
> +	else
> +		return false;
> +};
> +
> +static bool dce6_check_latency_hiding(struct dce6_wm_params *wm)
> +{
> +	u32 lb_partitions = wm->lb_size / wm->src_width;
> +	u32 line_time = wm->active_time + wm->blank_time;
> +	u32 latency_tolerant_lines;
> +	u32 latency_hiding;
> +	fixed20_12 a;
> +
> +	a.full = dfixed_const(1);
> +	if (wm->vsc.full > a.full)
> +		latency_tolerant_lines = 1;
> +	else {
> +		if (lb_partitions <= (wm->vtaps + 1))
> +			latency_tolerant_lines = 1;
> +		else
> +			latency_tolerant_lines = 2;
> +	}
> +
> +	latency_hiding = (latency_tolerant_lines * line_time + wm->blank_time);
> +
> +	if (dce6_latency_watermark(wm) <= latency_hiding)
> +		return true;
> +	else
> +		return false;
> +}
> +
> +static void dce6_program_watermarks(struct radeon_device *rdev,
> +					 struct radeon_crtc *radeon_crtc,
> +					 u32 lb_size, u32 num_heads)
> +{
> +	struct drm_display_mode *mode = &radeon_crtc->base.mode;
> +	struct dce6_wm_params wm;
> +	u32 pixel_period;
> +	u32 line_time = 0;
> +	u32 latency_watermark_a = 0, latency_watermark_b = 0;
> +	u32 priority_a_mark = 0, priority_b_mark = 0;
> +	u32 priority_a_cnt = PRIORITY_OFF;
> +	u32 priority_b_cnt = PRIORITY_OFF;
> +	u32 tmp, arb_control3;
> +	fixed20_12 a, b, c;
> +
> +	if (radeon_crtc->base.enabled && num_heads && mode) {
> +		pixel_period = 1000000 / (u32)mode->clock;
> +		line_time = min((u32)mode->crtc_htotal * pixel_period, (u32)65535);
> +		priority_a_cnt = 0;
> +		priority_b_cnt = 0;
> +
> +		wm.yclk = rdev->pm.current_mclk * 10;
> +		wm.sclk = rdev->pm.current_sclk * 10;
> +		wm.disp_clk = mode->clock;
> +		wm.src_width = mode->crtc_hdisplay;
> +		wm.active_time = mode->crtc_hdisplay * pixel_period;
> +		wm.blank_time = line_time - wm.active_time;
> +		wm.interlaced = false;
> +		if (mode->flags & DRM_MODE_FLAG_INTERLACE)
> +			wm.interlaced = true;
> +		wm.vsc = radeon_crtc->vsc;
> +		wm.vtaps = 1;
> +		if (radeon_crtc->rmx_type != RMX_OFF)
> +			wm.vtaps = 2;
> +		wm.bytes_per_pixel = 4; /* XXX: get this from fb config */
> +		wm.lb_size = lb_size;
> +		wm.dram_channels = dce6_get_number_of_dram_channels(rdev);
> +		wm.num_heads = num_heads;
> +
> +		/* set for high clocks */
> +		latency_watermark_a = min(dce6_latency_watermark(&wm), (u32)65535);
> +		/* set for low clocks */
> +		/* wm.yclk = low clk; wm.sclk = low clk */
> +		latency_watermark_b = min(dce6_latency_watermark(&wm), (u32)65535);
> +
> +		/* possibly force display priority to high */
> +		/* should really do this at mode validation time... */
> +		if (!dce6_average_bandwidth_vs_dram_bandwidth_for_display(&wm) ||
> +		    !dce6_average_bandwidth_vs_available_bandwidth(&wm) ||
> +		    !dce6_check_latency_hiding(&wm) ||
> +		    (rdev->disp_priority == 2)) {
> +			DRM_DEBUG_KMS("force priority to high\n");
> +			priority_a_cnt |= PRIORITY_ALWAYS_ON;
> +			priority_b_cnt |= PRIORITY_ALWAYS_ON;
> +		}
> +
> +		a.full = dfixed_const(1000);
> +		b.full = dfixed_const(mode->clock);
> +		b.full = dfixed_div(b, a);
> +		c.full = dfixed_const(latency_watermark_a);
> +		c.full = dfixed_mul(c, b);
> +		c.full = dfixed_mul(c, radeon_crtc->hsc);
> +		c.full = dfixed_div(c, a);
> +		a.full = dfixed_const(16);
> +		c.full = dfixed_div(c, a);
> +		priority_a_mark = dfixed_trunc(c);
> +		priority_a_cnt |= priority_a_mark & PRIORITY_MARK_MASK;
> +
> +		a.full = dfixed_const(1000);
> +		b.full = dfixed_const(mode->clock);
> +		b.full = dfixed_div(b, a);
> +		c.full = dfixed_const(latency_watermark_b);
> +		c.full = dfixed_mul(c, b);
> +		c.full = dfixed_mul(c, radeon_crtc->hsc);
> +		c.full = dfixed_div(c, a);
> +		a.full = dfixed_const(16);
> +		c.full = dfixed_div(c, a);
> +		priority_b_mark = dfixed_trunc(c);
> +		priority_b_cnt |= priority_b_mark & PRIORITY_MARK_MASK;
> +	}
> +
> +	/* select wm A */
> +	arb_control3 = RREG32(DPG_PIPE_ARBITRATION_CONTROL3 + radeon_crtc->crtc_offset);
> +	tmp = arb_control3;
> +	tmp &= ~LATENCY_WATERMARK_MASK(3);
> +	tmp |= LATENCY_WATERMARK_MASK(1);
> +	WREG32(DPG_PIPE_ARBITRATION_CONTROL3 + radeon_crtc->crtc_offset, tmp);
> +	WREG32(DPG_PIPE_LATENCY_CONTROL + radeon_crtc->crtc_offset,
> +	       (LATENCY_LOW_WATERMARK(latency_watermark_a) |
> +		LATENCY_HIGH_WATERMARK(line_time)));
> +	/* select wm B */
> +	tmp = RREG32(DPG_PIPE_ARBITRATION_CONTROL3 + radeon_crtc->crtc_offset);
> +	tmp &= ~LATENCY_WATERMARK_MASK(3);
> +	tmp |= LATENCY_WATERMARK_MASK(2);
> +	WREG32(DPG_PIPE_ARBITRATION_CONTROL3 + radeon_crtc->crtc_offset, tmp);
> +	WREG32(DPG_PIPE_LATENCY_CONTROL + radeon_crtc->crtc_offset,
> +	       (LATENCY_LOW_WATERMARK(latency_watermark_b) |
> +		LATENCY_HIGH_WATERMARK(line_time)));
> +	/* restore original selection */
> +	WREG32(DPG_PIPE_ARBITRATION_CONTROL3 + radeon_crtc->crtc_offset, arb_control3);
> +
> +	/* write the priority marks */
> +	WREG32(PRIORITY_A_CNT + radeon_crtc->crtc_offset, priority_a_cnt);
> +	WREG32(PRIORITY_B_CNT + radeon_crtc->crtc_offset, priority_b_cnt);
> +
> +}
> +
> +void dce6_bandwidth_update(struct radeon_device *rdev)
> +{
> +	struct drm_display_mode *mode0 = NULL;
> +	struct drm_display_mode *mode1 = NULL;
> +	u32 num_heads = 0, lb_size;
> +	int i;
> +
> +	radeon_update_display_priority(rdev);
> +
> +	for (i = 0; i < rdev->num_crtc; i++) {
> +		if (rdev->mode_info.crtcs[i]->base.enabled)
> +			num_heads++;
> +	}
> +	for (i = 0; i < rdev->num_crtc; i += 2) {
> +		mode0 = &rdev->mode_info.crtcs[i]->base.mode;
> +		mode1 = &rdev->mode_info.crtcs[i+1]->base.mode;
> +		lb_size = dce6_line_buffer_adjust(rdev, rdev->mode_info.crtcs[i], mode0, mode1);
> +		dce6_program_watermarks(rdev, rdev->mode_info.crtcs[i], lb_size, num_heads);
> +		lb_size = dce6_line_buffer_adjust(rdev, rdev->mode_info.crtcs[i+1], mode1, mode0);
> +		dce6_program_watermarks(rdev, rdev->mode_info.crtcs[i+1], lb_size, num_heads);
> +	}
> +}
> +
> diff --git a/drivers/gpu/drm/radeon/sid.h b/drivers/gpu/drm/radeon/sid.h
> new file mode 100644
> index 0000000..962cc17
> --- /dev/null
> +++ b/drivers/gpu/drm/radeon/sid.h
> @@ -0,0 +1,46 @@
> +/*
> + * Copyright 2011 Advanced Micro Devices, Inc.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
> + * OTHER DEALINGS IN THE SOFTWARE.
> + *
> + * Authors: Alex Deucher
> + */
> +#ifndef SI_H
> +#define SI_H
> +
> +#define MC_SHARED_CHMAP						0x2004
> +#define		NOOFCHAN_SHIFT					12
> +#define		NOOFCHAN_MASK					0x0000f000
> +
> +#define	DC_LB_MEMORY_SPLIT					0x6b0c
> +#define		DC_LB_MEMORY_CONFIG(x)				((x) << 20)
> +
> +#define	PRIORITY_A_CNT						0x6b18
> +#define		PRIORITY_MARK_MASK				0x7fff
> +#define		PRIORITY_OFF					(1 << 16)
> +#define		PRIORITY_ALWAYS_ON				(1 << 20)
> +#define	PRIORITY_B_CNT						0x6b1c
> +
> +#define	DPG_PIPE_ARBITRATION_CONTROL3				0x6cc8
> +#       define LATENCY_WATERMARK_MASK(x)			((x) << 16)
> +#define	DPG_PIPE_LATENCY_CONTROL				0x6ccc
> +#       define LATENCY_LOW_WATERMARK(x)				((x) << 0)
> +#       define LATENCY_HIGH_WATERMARK(x)			((x) << 16)
> +
> +#endif

No more comments, really it's fine as is.

Cheers,
Jerome