On Wed Apr 1 18:25:47 2026 +0200, Marco Nenciarini wrote:
> The get_hsfreq_by_mbps() function searches the freqranges[] table
> backward (from highest to lowest index). Because adjacent frequency
> bands overlap, a data rate that falls in the overlap region always
> lands on the higher-indexed band.
>
> For data rates up to 1500 Mbps (index 42) every band uses
> osc_freq_target 335. Starting at index 43 (1461-1640 Mbps) the
> osc_freq_target drops to 208. A sensor running at 1498 Mbps sits in
> the overlap between index 42 (1414-1588, osc 335) and index 43
> (1461-1640, osc 208). The backward search picks index 43, programming
> the lower osc_freq_target of 208 instead of the optimal 335.
>
> This causes DDL lock instability and CSI-2 CRC errors on affected
> configurations, such as the OmniVision OV08X40 sensor on Intel Arrow
> Lake platforms (Dell Pro Max 16).
>
> Rewrite get_hsfreq_by_mbps() to select the optimal band:
>
> 1. Among bands whose min/max range covers the data rate, prefer
> the one with the higher osc_freq_target.
> 2. If osc_freq_target is equal, prefer the band whose default_mbps
> is closest to the requested rate.
>
> Since the frequency ranges are monotonically increasing, the loop
> exits early once min exceeds the requested rate.
>
> For 1498 Mbps this now correctly selects index 42 (osc_freq_target
> 335, range 1414-1588) instead of index 43 (osc_freq_target 208,
> range 1461-1640).
>
> Fixes: 1e7eeb301696 ("media: intel/ipu6: add the CSI2 DPHY implementation")
> Cc: [email protected]
> Signed-off-by: Marco Nenciarini <[email protected]>
> Signed-off-by: Sakari Ailus <[email protected]>
Patch committed.
Thanks,
Sakari Ailus
drivers/media/pci/intel/ipu6/ipu6-isys-dwc-phy.c | 26 +++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)
---
diff --git a/drivers/media/pci/intel/ipu6/ipu6-isys-dwc-phy.c
b/drivers/media/pci/intel/ipu6/ipu6-isys-dwc-phy.c
index db2874843453..237906cb131a 100644
--- a/drivers/media/pci/intel/ipu6/ipu6-isys-dwc-phy.c
+++ b/drivers/media/pci/intel/ipu6/ipu6-isys-dwc-phy.c
@@ -288,15 +288,27 @@ static const struct dwc_dphy_freq_range
freqranges[DPHY_FREQ_RANGE_NUM] = {
static u16 get_hsfreq_by_mbps(u32 mbps)
{
- unsigned int i = DPHY_FREQ_RANGE_NUM;
-
- while (i--) {
- if (freqranges[i].default_mbps == mbps ||
- (mbps >= freqranges[i].min && mbps <= freqranges[i].max))
- return i;
+ u16 best = DPHY_FREQ_RANGE_INVALID_INDEX;
+ unsigned int i;
+
+ for (i = 0; i < DPHY_FREQ_RANGE_NUM; i++) {
+ if (mbps > freqranges[i].max)
+ continue;
+
+ if (mbps < freqranges[i].min)
+ break;
+
+ if (best == DPHY_FREQ_RANGE_INVALID_INDEX ||
+ freqranges[i].osc_freq_target >
+ freqranges[best].osc_freq_target ||
+ (freqranges[i].osc_freq_target ==
+ freqranges[best].osc_freq_target &&
+ abs((int)mbps - (int)freqranges[i].default_mbps) <
+ abs((int)mbps - (int)freqranges[best].default_mbps)))
+ best = i;
}
- return DPHY_FREQ_RANGE_INVALID_INDEX;
+ return best;
}
static int ipu6_isys_dwc_phy_config(struct ipu6_isys *isys,
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