-----Original Message----- From: Deak, Imre imre.deak@intel.com Sent: Monday, 12 May 2025 23.26 To: Sousa, Gustavo gustavo.sousa@intel.com Cc: intel-gfx@lists.freedesktop.org; intel-xe@lists.freedesktop.org; Kahola, Mika mika.kahola@intel.com; stable@vger.kernel.org Subject: Re: [PATCH] drm/i915/ptl: Use everywhere the correct DDI port clock select mask
On Mon, May 12, 2025 at 05:03:52PM -0300, Gustavo Sousa wrote:
Quoting Imre Deak (2025-05-12 11:26:00-03:00)
[...]
diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h b/drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h index 960f7f778fb81..59c22beaf1de5 100644 --- a/drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy_regs.h @@ -192,10 +192,17 @@
#define XELPDP_TBT_CLOCK_REQUEST REG_BIT(19) #define XELPDP_TBT_CLOCK_ACK REG_BIT(18) -#define XELPDP_DDI_CLOCK_SELECT_MASK
REG_GENMASK(15, 12)
-#define XE3_DDI_CLOCK_SELECT_MASK REG_GENMASK(16,
-#define XELPDP_DDI_CLOCK_SELECT(val)
REG_FIELD_PREP(XELPDP_DDI_CLOCK_SELECT_MASK, val)
-#define XE3_DDI_CLOCK_SELECT(val)
REG_FIELD_PREP(XE3_DDI_CLOCK_SELECT_MASK, val)
+#define _XELPDP_DDI_CLOCK_SELECT_MASK
REG_GENMASK(15, 12)
+#define _XE3_DDI_CLOCK_SELECT_MASK REG_GENMASK(16,
Since bit 16 is unused for pre-Xe3 display IPs, I wonder if we should simply redefine XELPDP_DDI_CLOCK_SELECT_MASK to be REG_GENMASK(16,
and add a comment noting changes by display IP? Are we aware of something that would be wired to bit 16 that would prevent us from doing that?
Not sure if a register bit is not used, unless it's defined as reserved. For pre-Xe3 (pre-PTL) bits 16-17 are not defined as reserved.
Bits 16-17 are not defined or marked as reserved, so Imre's approach seems safe.
Tested-by: Mika Kahola mika.kahola@intel.com Reviewed-by: Mika Kahola mika.kahola@intel.com
I remember something similar was done to other register fields in the past. Some examples I found:
3fe856180c94 ("drm/i915/xe3lpd: Add new bit range of MAX swing setup") 247bdac958fc ("drm/i915/adl_p: Add ddb allocation support") d7e449a858ec ("drm/i915: Just use icl+ definition for PLANE_WMblocks field")
-- Gustavo Sousa
+#define XELPDP_DDI_CLOCK_SELECT_MASK(display)
(DISPLAY_VER(display) >= 30 ? \
_XE3_DDI_CLOCK_SELECT_MASK :_XELPDP_DDI_CLOCK_SELECT_MASK)
+#define XELPDP_DDI_CLOCK_SELECT_PREP(display, val)
(DISPLAY_VER(display) >= 30 ? \
REG_FIELD_PREP(_XE3_DDI_CLOCK_SELECT_MASK, (val)) : \
REG_FIELD_PREP(_XELPDP_DDI_CLOCK_SELECT_MASK, (val)))
+#define XELPDP_DDI_CLOCK_SELECT_GET(display, val)
(DISPLAY_VER(display) >= 30 ? \
REG_FIELD_GET(_XE3_DDI_CLOCK_SELECT_MASK, (val)) : \
+REG_FIELD_GET(_XELPDP_DDI_CLOCK_SELECT_MASK, (val)))
#define XELPDP_DDI_CLOCK_SELECT_NONE 0x0 #define XELPDP_DDI_CLOCK_SELECT_MAXPCLK 0x8
#define XELPDP_DDI_CLOCK_SELECT_DIV18CLK 0x9
2.44.2