pci_get_rom_size(9)

💖 pci_get_rom_size(9) 💖

okay so bestie, we're in the Kernel API Manual today and the star of the show is pci_get_rom_size — the little function that tells you how big a ROM image actually is 👑 no cap.

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✨ NAME ✨

pci_get_rom_size — obtain the actual size of the ROM image 🎀

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✨ SYNOPSIS ✨

size_t pci_get_rom_size (struct pci_dev *pdev , void __iomem *rom ,
       size_t size );

literally right there, copy it exactly, don't be weird about the spacing 🫶

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✨ ARGUMENTS ✨

• pdev — target PCI device. the one we're snooping on 💅
• rom — kernel virtual pointer to image of ROM. yes, a kernel virtual pointer, stay in your lane 🔥
• size — size of PCI window. the big floppy outer box, not the actual picture inside, iykyk 😭

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✨ RETURN ✨

size of actual ROM image ⭐ that's the whole point, that's the payoff, that's the main character moment.

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✨ DESCRIPTION ✨

so the vibe is: determine the actual length of the ROM image 🌸 because here's the tea — the PCI window size could be much larger than the actual image size 💀 like, dramatically larger. the window is giving oversized hoodie and the image inside is giving tiny little guy. this function does the vibe check and hands you the real number ✨

lowkey important: size is the window, the return value is the image. do not get these two confused or it's over for you 🙈

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✨ SEE ALSO ✨

• Kernel file ./drivers/pci/rom.c
• pci_enable_rom(9)
• pci_disable_rom(9)
• pci_map_rom(9)
• pci_unmap_rom(9)

go read the whole squad fr fr, they're all in ./drivers/pci/rom.c and they ate 🍓

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and that's the page bestie!! brought to you by ./drivers/pci in October 2026, fresh out of the Kernel API Manual 💜 mwah, go size some ROMs responsibly 🧚💖