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V4L/DVB (5578): Workaround for bad hardare/firmware on some pluto2 devices

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pluto2_driver: Workaround for pluto2 card reporting wrong number of
received packets and flooding system with interrupts.

This patch constitutes a workaround for a hardware/firmware problem of the
pluto2-based card (e.g., Satelco EasyWatch).

It can happen in rare cases that the card gets into a mode where it
always reports back a number of received packets (nbpackets) which is
larger than the maximum permissible number of packets (TS_DMA_PACKETS).
The workaround that is already in the driver in function pluto_dma_end
reports back zero received packets. In spite of the (in reality) zero
received packets the card continues to generate interrupts at a very
high rate, which can effectively stall the system.

The patch resets the TS logic, which puts the card back into normal
operations.

Signed-off-by: Holger Magnussen <holger@muscate-magnussen.de>
Signed-off-by: Andreas Oberritter <obi@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
This commit is contained in:
holger@muscate-magnussen.de 2007-05-01 09:25:56 -03:00 committed by Mauro Carvalho Chehab
parent ba70d59bb9
commit 4d84517001
1 changed files with 8 additions and 0 deletions
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8
drivers/media/dvb/pluto2/pluto2.c
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@ -293,12 +293,20 @@ static void pluto_dma_end(struct pluto *pluto, unsigned int nbpackets)
* but no packets have been transfered.
* [2] Sometimes (actually very often) NBPACKETS stays at zero
* although one packet has been transfered.
* [3] Sometimes (actually rarely), the card gets into an erroneous
* mode where it continuously generates interrupts, claiming it
* has recieved nbpackets>TS_DMA_PACKETS packets, but no packet
* has been transfered. Only a reset seems to solve this
*/
if ((nbpackets == 0) || (nbpackets > TS_DMA_PACKETS)) {
unsigned int i = 0;
while (pluto->dma_buf[i] == 0x47)
i += 188;
nbpackets = i / 188;
if (i == 0) {
pluto_reset_ts(pluto, 1);
dev_printk(KERN_DEBUG, &pluto->pdev->dev, "resetting TS because of invalid packet counter\n");
}
}
dvb_dmx_swfilter_packets(&pluto->demux, pluto->dma_buf, nbpackets);