STRUCT XE_REG(9)

🎀 struct xe_reg(9) 🎀

okay bestie, so this is a page from the Kernel API Manual — yes, the actual kernel manual, and we're about to make it make sense. welcome to struct xe_reg, the little register definition that could. 🦋

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✨ NAME ✨

struct xe_reg — Register definition 💅

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✨ SYNOPSIS ✨

struct xe_reg {
    union {
      struct {
        u32 addr:const_ilog2(XE_REG_ADDR_MAX);
        u32 masked:1;
        u32 mcr:1;
        u32 vf:1;
      };
      u32 raw;
    };
 };

like, look at her. bitfields AND a union. main character energy honestly. 👑

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✨ Members ✨

• {unnamed_union} — anonymous 🫶 (she has no name, she's mysterious, she's a union)
• {unnamed_struct} — anonymous too 🙈 (struct with no name, we love a lowkey icon)
• addr — address 📍
• masked — this register is "masked", meaning the upper 16 bits are used to identify which bits get updated on the lower bits ✨ (yes, 16 whole bits doing identification duty, no cap)
• mcr — register is multicast/replicated in the hardware and needs special handling ⚠️. literally any register with this set should also use a type of xe_reg_mcr_t. it's only here so the few places that deal with MCR registers specially (xe_sr.c) and tests using the raw value can inspect it 👀
• vf — register is accessible from the Virtual Function 💜
• raw — Raw value with both address and options 🔥 (the whole thing, packed up, one u32, iconic)

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✨ Description ✨

so basically 🧚 this is the register definition that gets used by the individual register. and here's the plot twist: even though the same definition is used for both xe_reg and xe_reg_mcr, they use different internal APIs for accesses. same fit, different function. periodt. 💅

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✨ SEE ALSO ✨

• Kernel file ./drivers/gpu/drm/xe/regs/xe_reg_defs.h
• XE_REG_ADDR_MAX(9)
• struct xe_reg_mcr(9)
• XE_REG_OPTION_MASKED(9)
• XE_REG_OPTION_VF(9)
• XE_REG_INITIALIZER(9)
• XE_REG(9)
• XE_REG_MCR(9)

go read them, i'll wait. 💖 🌸

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ok that's the whole page bestie, no notes. 🎀

and for the cute sign-off: this icon lives over in ./drivers/gpu/drm/xe/regs, dated October 2026, and you can find her again any time at struct xe_reg(9). 🦋✨ bye ily! 🌈