The ESS1788 sound chip is supported by the Linux kernel, but is not listed
as supported by Red Hat Linux nor is it recognised by sndconfig (upto
version 0.57), which claims that no plug-and-play sound cards are detected,
and doesn't list it as an option. The options for ESS688, ESS1688 and
ESS1868 don't work properly (MIDI OK, wave files play too slow).

The following /etc/modules.conf file will allow sound to work properly on a
Rock Mentor 520 laptop, which uses the ESS1788. Hope this information is of
some use if you feel like adding support for this device, whether on an
"informal/unsupported but works anyway" basis or otherwise.

alias sound-slot-0 sb
options sound dmabuf=1
alias midi opl3
options opl3 io=0x388
options sb io=0x220 irq=7 dma=1 mpu_io=0x320 esstype=1788