From 6df388f2d549d3a2a7ad58b632d2ecd25fc0ff3f Mon Sep 17 00:00:00 2001 From: Hannes Reinecke Date: Mon, 24 Nov 2014 15:37:26 +0100 Subject: am53c974: BLAST residual handling The am53c974 has an design issue where a single byte might be left in the SCSI FIFO after a DMA transfer. As the handling code is currently untested add a WARN_ON() statement here. Reviewed-by: Paolo Bonzini Acked-by: David S. Miller Signed-off-by: Hannes Reinecke Signed-off-by: Christoph Hellwig --- drivers/scsi/am53c974.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/scsi/am53c974.c') diff --git a/drivers/scsi/am53c974.c b/drivers/scsi/am53c974.c index a16c9cf0f0a2..a42e8db057a4 100644 --- a/drivers/scsi/am53c974.c +++ b/drivers/scsi/am53c974.c @@ -200,6 +200,12 @@ static void pci_esp_dma_drain(struct esp *esp) } pci_esp_write8(esp, ESP_DMA_CMD_DIR | ESP_DMA_CMD_IDLE, ESP_DMA_CMD); esp_dma_log("DMA blast done (%d tries, %d bytes left)\n", lim, resid); + /* BLAST residual handling is currently untested */ + if (WARN_ON_ONCE(resid == 1)) { + struct esp_cmd_entry *ent = esp->active_cmd; + + ent->flags |= ESP_CMD_FLAG_RESIDUAL; + } } static void pci_esp_dma_invalidate(struct esp *esp) -- cgit v1.2.3