Hi, I used to have the problem described by Branden Robinson in a previous mail on DebianPPC: a Samsung CDRW/DVD that would not eject discs nor play, nor anything. I patched a 2.4.24-ben1 with your code and now the CD features are working fine. I didn't test burning CDs or playing DVDs yet.
Cheers,
Marco
Le dim 15/02/2004 à 03:48, Benjamin Herrenschmidt a écrit :
> Hi !
>
> Recently, there have been lost of reports of ATAPI issues, typically
> with CD/DVD burners, where DMA would be disabled for no obvious reasons,
> with the driver spitting a message about a timeout waiting for dbdma
> command stop.
>
> The problem is that our driver doesn't deal with buffer underruns due
> to the drive not sending as many data as requested.
>
> This patch is an attempt at fixing this. Please let me know if it
> helps.
>
> Ben.
>
> ===== drivers/ide/ppc/pmac.c 1.50 vs edited =====
> --- 1.50/drivers/ide/ppc/pmac.c Sat Feb 14 19:29:16 2004
> +++ edited/drivers/ide/ppc/pmac.c Sun Feb 15 13:47:12 2004
> @@ -55,7 +55,7 @@
>
> #define IDE_PMAC_DEBUG
>
> -#define DMA_WAIT_TIMEOUT 100
> +#define DMA_WAIT_TIMEOUT 50
>
> typedef struct pmac_ide_hwif {
> unsigned long regbase;
> @@ -2032,8 +2032,11 @@
> dstat = readl(&dma->status);
> writel(((RUN|WAKE|DEAD) << 16), &dma->control);
> pmac_ide_destroy_dmatable(drive);
> - /* verify good dma status */
> - return (dstat & (RUN|DEAD|ACTIVE)) != RUN;
> + /* verify good dma status. we don't check for ACTIVE beeing 0. We
> should...
> + * in theory, but with ATAPI decices doing buffer underruns, that would
> + * cause us to disable DMA, which isn't what we want
> + */
> + return (dstat & (RUN|DEAD)) != RUN;
> }
>
> /*
> @@ -2047,7 +2050,7 @@
> {
> pmac_ide_hwif_t* pmif = (pmac_ide_hwif_t *)HWIF(drive)->hwif_data;
> volatile struct dbdma_regs *dma;
> - unsigned long status;
> + unsigned long status, timeout;
>
> if (pmif == NULL)
> return 0;
> @@ -2063,17 +2066,8 @@
> * - The dbdma fifo hasn't yet finished flushing to
> * to system memory when the disk interrupt occurs.
> *
> - * The trick here is to increment drive->waiting_for_dma,
> - * and return as if no interrupt occurred. If the counter
> - * reach a certain timeout value, we then return 1. If
> - * we really got the interrupt, it will happen right away
> - * again.
> - * Apple's solution here may be more elegant. They issue
> - * a DMA channel interrupt (a separate irq line) via a DBDMA
> - * NOP command just before the STOP, and wait for both the
> - * disk and DBDMA interrupts to have completed.
> */
> -
> +
> /* If ACTIVE is cleared, the STOP command have passed and
> * transfer is complete.
> */
> @@ -2085,15 +2079,26 @@
> called while not waiting\n", HWIF(drive)->index);
>
> /* If dbdma didn't execute the STOP command yet, the
> - * active bit is still set */
> - drive->waiting_for_dma++;
> - if (drive->waiting_for_dma >= DMA_WAIT_TIMEOUT) {
> - printk(KERN_WARNING "ide%d, timeout waiting \
> - for dbdma command stop\n", HWIF(drive)->index);
> - return 1;
> - }
> - udelay(5);
> - return 0;
> + * active bit is still set. We consider that we aren't
> + * sharing interrupts (which is hopefully the case with
> + * those controllers) and so we just try to flush the
> + * channel for pending data in the fifo
> + */
> + udelay(1);
> + writel((FLUSH << 16) | FLUSH, &dma->control);
> + timeout = 0;
> + for (;;) {
> + udelay(1);
> + status = readl(&dma->status);
> + if ((status & FLUSH) == 0)
> + break;
> + if (++timeout > 100) {
> + printk(KERN_WARNING "ide%d, ide_dma_test_irq \
> + timeout flushing channel\n", HWIF(drive)->index);
> + break;
> + }
> + }
> + return 1;
> }
>
> static int __pmac
>
>
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