diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-06-07 17:09:03 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-06-07 17:09:03 -0700 |
| commit | 4d3d769c605ebdf9fbb5a9d63827598b48351861 (patch) | |
| tree | b71d8faa40a026b2ed68a24ab25ccfd514cf45f3 /drivers/ata/sata_via.c | |
| parent | cfca31ce789963c0dd6ca2e9cc13b90cc2802fbd (diff) | |
| parent | 0ee719527229fa86ace8e3abccae3c2a8bbfd6db (diff) | |
Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev
* 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzik/libata-dev:
ahci: redo stopping DMA engines on empty ports
sata_sil24: fix kernel panic on ARM caused by unaligned access in sata_sil24
ahci: add pci quirk for JMB362
sata_via: explain the magic fix
Diffstat (limited to 'drivers/ata/sata_via.c')
| -rw-r--r-- | drivers/ata/sata_via.c | 18 |
1 files changed, 16 insertions, 2 deletions
diff --git a/drivers/ata/sata_via.c b/drivers/ata/sata_via.c index 0ecd0f6aa2c..4730c42a5ee 100644 --- a/drivers/ata/sata_via.c +++ b/drivers/ata/sata_via.c @@ -578,10 +578,24 @@ static void svia_configure(struct pci_dev *pdev) /* * vt6421 has problems talking to some drives. The following - * is the magic fix from Joseph Chan <JosephChan@via.com.tw>. - * Please add proper documentation if possible. + * is the fix from Joseph Chan <JosephChan@via.com.tw>. + * + * When host issues HOLD, device may send up to 20DW of data + * before acknowledging it with HOLDA and the host should be + * able to buffer them in FIFO. Unfortunately, some WD drives + * send upto 40DW before acknowledging HOLD and, in the + * default configuration, this ends up overflowing vt6421's + * FIFO, making the controller abort the transaction with + * R_ERR. + * + * Rx52[2] is the internal 128DW FIFO Flow control watermark + * adjusting mechanism enable bit and the default value 0 + * means host will issue HOLD to device when the left FIFO + * size goes below 32DW. Setting it to 1 makes the watermark + * 64DW. * * https://bugzilla.kernel.org/show_bug.cgi?id=15173 + * http://article.gmane.org/gmane.linux.ide/46352 */ if (pdev->device == 0x3249) { pci_read_config_byte(pdev, 0x52, &tmp8); |