megasas_set_dma_mask(9)

📦 version 7.3.1, in nixpkgs unstable

💅 megasas_set_dma_mask — Kernel API Manual ✨

okay so bestie, welcome to the megasas_set_dma_mask page, straight out of the Linux Kernel API Manual. she's a tiny function with a big job: deciding how many DMA address bits your MegaRAID controller gets to play with. let's get into it 🫶

🌸 NAME 🌸

megasas_set_dma_mask — set the DMA mask for the supported controllers, no cap 💅

✨ SYNOPSIS ✨

int megasas_set_dma_mask (struct megasas_instance *instance );

🎀 ARGUMENTS 🎀

  • instance — the adapter soft state. that's it, that's the whole argument, she's low maintenance 💖

🦋 DESCRIPTION 🦋

okay so this is the part where it gets controller-specific, and honestly it's giving "different friend groups, different vibes." here's the tea per controller fam:

For Ventura — the driver and the firmware will operate in 63bit DMA addresses. living large, highkey iconic 👑

For invader — by default, the driver and firmware will operate in 32bit DMA addresses for consistent DMA mapping. BUT (and this is the important bit 🫶) if the 32 bit consistent DMA mask fails, the driver will try with a 63 bit consistent mask — provided the FW is true 63bit DMA capable. so it's a fallback situation, not a free-for-all. the firmware has to actually be capable, iykyk.

For older controllers (Thunderbolt and MFI based adapters) — the driver and firmware will operate in 32 bit consistent DMA addresses. no 63 bit dreams for these elders, they're chilling in 32 bits periodt 🙈

lowkey the whole point of this function: make sure the DMA mask matches what the controller and firmware can actually handle. don't skip the vibe check 💀

🌈 SEE ALSO 🌈

first up, the kernel file where all this lives:

  • ./drivers/scsi/megaraid/megaraid_sas_base.c

and now the full friend group — every single one of these, no skips, we don't leave anybody out 🥹:

that's the whole roster, 93 entries and we're not dropping a single one 💀✨

and that's the page bestie!! 🎀 mwah, go forth and DMA responsibly 💖

this gorgeousness came from ./drivers/scsi/megaraid, and she was dated October 2026 — screenshot it, frame it, it's giving archival icon behavior 👑🦋

📦 where this page comes from