Modesetting driver cannot exceed pipeline dimensions reported by kernel (8192x8192). The old intel driver could.
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
X.Org X server |
Unknown
|
Unknown
|
|||
xorg-server (Ubuntu) |
Triaged
|
Medium
|
Unassigned |
Bug Description
The i915 driver in the Linux kernel misrepresents the max output of certain, newer, GPUs.
The output should be 16384x16384 for newer models (on at least 7th and 8th gen Intel CPUs) but it is stuck in 8192x8192.
The problem lies in: https:/
The conditional branch which is wrong is:
/* maximum framebuffer dimensions */
if (IS_GEN2(dev_priv)) {
dev->mode_
dev->mode_
} else if (IS_GEN3(dev_priv)) {
dev->mode_
dev->mode_
} else {
dev->mode_
dev->mode_
}
While I'm not certain which generations specifically allows the higher output it is most certainly true of all iGPUs on the 7th and 8th generation CPUs.
This is corroborated by Intel's own hardware pages, and can be proven by running Wayland which ignores the limitation in the driver.
Bug is present both on all Ubuntu releases, including 18.04.
affects: | xorg (Ubuntu) → linux (Ubuntu) |
Update. This is a functional regression as a result of switching to modesetting. /bugs.freedeskt op.org/ show_bug. cgi?id= 107840# c1
Source: https:/