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drm/i915: Make data/link N value power of two

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The BIOS uses power of two values for the data/link N value.

Follow suit to make the Zotac DP to dual-HDMI dongle work.

v2: Clean up the magic numbers and defines
    Change the N clamping to be a bit easier on the eye
    Rename intel_reduce_ratio to intel_reduce_m_n_ratio

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=49402
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=59810
Tested-by:  Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
This commit is contained in:
Ville Syrjälä 2013-04-23 15:03:34 +03:00 committed by Daniel Vetter
parent ae4edb8089
commit a65851af59
2 changed files with 22 additions and 16 deletions
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12
drivers/gpu/drm/i915/i915_reg.h
View file

@ -2652,14 +2652,14 @@
#define _PIPEB_GMCH_DATA_M 0x71050
/* Transfer unit size for display port - 1, default is 0x3f (for TU size 64) */
#define PIPE_GMCH_DATA_M_TU_SIZE_MASK (0x3f << 25)
#define PIPE_GMCH_DATA_M_TU_SIZE_SHIFT 25
#define TU_SIZE(x) (((x)-1) << 25) /* default size 64 */
#define TU_SIZE_MASK (0x3f << 25)
#define PIPE_GMCH_DATA_M_MASK (0xffffff)
#define DATA_LINK_M_N_MASK (0xffffff)
#define DATA_LINK_N_MAX (0x800000)
#define _PIPEA_GMCH_DATA_N 0x70054
#define _PIPEB_GMCH_DATA_N 0x71054
#define PIPE_GMCH_DATA_N_MASK (0xffffff)
/*
* Computing Link M and N values for the Display Port link
@ -2674,11 +2674,9 @@
#define _PIPEA_DP_LINK_M 0x70060
#define _PIPEB_DP_LINK_M 0x71060
#define PIPEA_DP_LINK_M_MASK (0xffffff)
#define _PIPEA_DP_LINK_N 0x70064
#define _PIPEB_DP_LINK_N 0x71064
#define PIPEA_DP_LINK_N_MASK (0xffffff)
#define PIPE_GMCH_DATA_M(pipe) _PIPE(pipe, _PIPEA_GMCH_DATA_M, _PIPEB_GMCH_DATA_M)
#define PIPE_GMCH_DATA_N(pipe) _PIPE(pipe, _PIPEA_GMCH_DATA_N, _PIPEB_GMCH_DATA_N)
@ -3404,8 +3402,6 @@
#define _PIPEA_DATA_M1 (dev_priv->info->display_mmio_offset + 0x60030)
#define TU_SIZE(x) (((x)-1) << 25) /* default size 64 */
#define TU_SIZE_MASK 0x7e000000
#define PIPE_DATA_M1_OFFSET 0
#define _PIPEA_DATA_N1 (dev_priv->info->display_mmio_offset + 0x60034)
#define PIPE_DATA_N1_OFFSET 0

26
drivers/gpu/drm/i915/intel_display.c
View file

@ -4084,26 +4084,36 @@ static int i830_get_display_clock_speed(struct drm_device *dev)
}
static void
intel_reduce_ratio(uint32_t *num, uint32_t *den)
intel_reduce_m_n_ratio(uint32_t *num, uint32_t *den)
{
while (*num > 0xffffff || *den > 0xffffff) {
while (*num > DATA_LINK_M_N_MASK ||
*den > DATA_LINK_M_N_MASK) {
*num >>= 1;
*den >>= 1;
}
}
static void compute_m_n(unsigned int m, unsigned int n,
uint32_t *ret_m, uint32_t *ret_n)
{
*ret_n = min_t(unsigned int, roundup_pow_of_two(n), DATA_LINK_N_MAX);
*ret_m = div_u64((uint64_t) m * *ret_n, n);
intel_reduce_m_n_ratio(ret_m, ret_n);
}
void
intel_link_compute_m_n(int bits_per_pixel, int nlanes,
int pixel_clock, int link_clock,
struct intel_link_m_n *m_n)
{
m_n->tu = 64;
m_n->gmch_m = bits_per_pixel * pixel_clock;
m_n->gmch_n = link_clock * nlanes * 8;
intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
m_n->link_m = pixel_clock;
m_n->link_n = link_clock;
intel_reduce_ratio(&m_n->link_m, &m_n->link_n);
compute_m_n(bits_per_pixel * pixel_clock,
link_clock * nlanes * 8,
&m_n->gmch_m, &m_n->gmch_n);
compute_m_n(pixel_clock, link_clock,
&m_n->link_m, &m_n->link_n);
}
static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv)