The function topic97_zoom_video should be changed to the following:

static void topic97_zoom_video(struct pcmcia_socket *sock, int onoff)
{
	struct yenta_socket *socket = container_of(sock, struct yenta_socket, socket);
	u8 reg_zv, reg;

	reg_zv = config_readb(socket, TOPIC97_ZOOM_VIDEO_CONTROL);
	if (onoff) {
		reg_zv |= TOPIC97_ZV_CONTROL_ENABLE;
		config_writeb(socket, TOPIC97_ZOOM_VIDEO_CONTROL, reg_zv);
		reg = config_readb(socket, TOPIC97_AUDIO_VIDEO_SWITCH);
		reg |= TOPIC97_AVS_AUDIO_CONTROL | TOPIC97_AVS_VIDEO_CONTROL;
		config_writeb(socket, TOPIC97_AUDIO_VIDEO_SWITCH, reg);
	}
	else {
		reg_zv &= ~TOPIC97_ZV_CONTROL_ENABLE;
		config_writeb(socket, TOPIC97_ZOOM_VIDEO_CONTROL, reg_zv);

		reg = config_readb(socket, TOPIC97_AUDIO_VIDEO_SWITCH);
		reg &= ~(TOPIC97_AVS_AUDIO_CONTROL | TOPIC97_AVS_VIDEO_CONTROL);
		config_writeb(socket, TOPIC97_AUDIO_VIDEO_SWITCH, reg);
	}

}

It is hard to test as there are not many laptops that still have a Zoomed Video CardBus enabled or there are only a few pcmcia cards that support Zoomed Video
The one I know is the Libretto 100CT and 110CT with a Zoomed Video port that works with the Margi DVD-to-Go which streams the decoded DVD stream into the video overlay plane via the PCMCIA Zoomed Video port.

You can find more information at http://www.xs4all.nl/~avics/Setting%20up%20Margi%20DVD.html.

The information has been retrieved from the Topic manual which can be optained from Toshiba.

Please contact me at avi dot cohenstuart at infor dot com for questions.