A single developer has released an open-source Linux display driver that squeezes real capability out of an aging Silicon Motion SM750 graphics card, and the project is a small clinic in what open source does best. According to Hacker News, where the release climbed to 172 points, the driver is called sm750hdmifb (with the kernel module named sm750hdmidrm.ko) and it targets one very specific board: the single-HDMI SE-DP750A-HDMI PCIe card. The maker, who goes by KodeMunkie on GitHub, isn’t promising universal support. This is a focused fix for a card most vendors abandoned years ago.
What stands out here is the ambition packed into a chip normally described as topping out at 1920 pixels wide. This driver pushes it further.
What the driver actually does
- Unlocks real 2048-wide modes. With the edid_only=0 flag, the driver exposes genuine hardware resolutions like 2048×864, 2048×1024, 2048×1080, and 2048×1152 at refresh rates up to 75 Hz. These sit above the card’s normally published limits.
- Adds software-scaled ultrawide. Set softscale_wide=1 and you can drive a 2560×1080 ultrawide desktop, provided you own a physical ultrawide monitor with full widescreen stretch turned on in its menu.
- Saves bandwidth with smart color conversion. The SM750 framebuffer is reached over a slow PCIe 1.1 x1 link. To cope, the driver converts changed screen regions to 16-bit RGB565 with an ordered dither and a 94% green-channel correction. That halves the pixel traffic sent to the device (two bytes per pixel instead of four) while keeping most of the visible color detail.
- Optimizes updates for smoother performance. It coalesces updates on a worker, uploads eight-row batches over DMA, and falls back to CPU safely if DMA fails. A hardware cursor and latest-frame-only update logic keep things responsive.
Who can use it, and how
The driver is free and open source, published on GitHub. Ubuntu 24.04 and Linux Mint 22 users can build a DKMS package locally with a short sequence of apt and git commands, then install the resulting .deb and reboot. That reboot matters: it lets the package blacklist Linux’s old sm750fb driver before it can grab the card.
One firm requirement stands out. The driver targets Linux 6.17 and newer, and DKMS deliberately refuses older kernels because the required DRM interfaces simply aren’t there. It builds and passes its full test suite against 6.17 and 7.0 Ubuntu kernels. Prebuilt packages show up under GitHub Releases when available, but the author recommends building locally so DKMS compiles against your installed headers.
The caveats are real, and the author says so
This is where the project earns trust. The driver is labeled experimental, and the documentation is blunt about risk. The tested board must match an exact spec: a Silicon Motion SM750G10-AC revision A1, PCI ID 126f:0750, a Silicon Image/Lattice SiI9024ACNU HDMI transmitter, 16 MiB of memory, and one HDMI output. As the docs put it, “The PCI ID alone is not enough.” Other SM750 cards may use VGA or different wiring and won’t work.
Some flags carry outright warnings. Turning off EDID restrictions (edid_only=0) or enabling wide compression (softscale_wide=1) can push clocks past what your monitor supports, producing no signal, distortion, or an unstable display. The advice is practical: keep SSH or another recovery route open when trying non-EDID modes.
Why it matters
This is significant because it’s the open-source model working exactly as intended. A commercial vendor would never invest engineering hours resurrecting a niche 16 MiB card. One motivated developer did, documented every tradeoff honestly, and handed the result to anyone who owns the same board. It’s out-of-tree, so future kernels may need source updates, but the maintainer has already built compatibility paths through the 6.x series and into 7.0.
Small project, big principle. For anyone curious about the exact module parameters or build steps, the full write-up and code are available at the original source.