8dff0b6761
Mapping the framebuffer with WC (Write Combined) memory type can, in practice, cause some memory transactions to be rate-limited at a fraction of the fb write rate. WC allows one core to queue up many globally visible write transactions, and in the process some unrelated transactions may end up having to wait for all of the queued up PCI writes to be flushed. Add an hw.efifb.cache_attr tunable to allow mapping the framebuffer as uncacheable instead. We should likely be taking a more careful approach of checking the memory map to determine which cacheability attributes are feasible, but the knob lets us use our historically functional behavior while offering a convenient way to switch on a stock kernel. The only valid values for hw.efifb.cache_attr at this time are "uc" and "wc". Original patch by Marc De La Gueronniere <mdelagueronniere@verisign.com> along with previous testing. Reviewed by: imp MFC after: 1 week Sponsored by: Verisign, Inc. Sponsored by: Klara, Inc. Differential Revision: https://reviews.freebsd.org/D17884 |
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| colors | ||
| font | ||
| hw | ||
| logo | ||
| vt_buf.c | ||
| vt_consolectl.c | ||
| vt_core.c | ||
| vt_cpulogos.c | ||
| vt_font.c | ||
| vt_sysmouse.c | ||
| vt.h | ||